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Greatest Equations Ever

sgant writes "What is your favorite equation? This was the question asked by Physics World in a recent poll. This is also covered in a New York Times article about the same poll. Some of the equations mentioned were the simplistic 1+1=2 and Euler's equation, ei + 1 = 0. What are some of your favorite equations?"

1,017 comments

  1. correction by schematix · · Score: 5, Insightful

    Euler's equation is actually Exp[i*Pi] + 1 = 0 not Exp[i*n] +1 = 0 (unless they say n = Pi, which they don't). I'd have to say this is the most elegant equation of all time. It combines the 5 most important numbers in all of mathematics into a single formula. This formula also has tremendous applications in many fields of engineering and other areas of applied mathematics. If it wasn't for this equation, your cell phone wouldn't work.

    --
    Scott
    1. Re:correction by Enzo90910 · · Score: 0

      Quite true and such a mistake more or less disqualifies the whole paper in my mind. The guy doesn't know what he's talking about, nothing to learn here.

      --
      I don't have much to add.
    2. Re:correction by niks42 · · Score: 5, Insightful

      Actually, isn't Euler's formula Exp[i*theta] = cos[theta] + i*sin[theta] ? and then substitute in the value of pi into theta, and the more famous result appears.

    3. Re:correction by bsiggers · · Score: 1

      Also great is the derivation of this equation - one on the classic 'pulling a rabbit out of the hat' lecturer performances back in Uni.

    4. Re:correction by schematix · · Score: 1

      yes exactly

      --
      Scott
    5. Re:correction by Ford+Prefect · · Score: 5, Informative

      It combines the 5 most important numbers in all of mathematics into a single formula.

      It's also got the other important mathematical concepts - exponentiation (i.e. raising something to the power of something else), multiplication, addition and equals. Essentially, it's a huge nugget of maths in a tidy little wrapper.

      I've got an old Sharp graphics calculator, which has both proper notation layout and a complex numbers mode. I still like keying in the 'e^(pi*i)+1', pressing 'Enter', then getting the zero, all perfectly laid out on a little LCD display...

      --
      Tedious Bloggy Stuff - hooray?
    6. Re:correction by Anonymous Coward · · Score: 5, Informative

      There's a difference between "Euler's formula" and "Euler's Formula", depending on whether you're referring to one of his formulae or the specific formula called "Euler's Formula".

      Guy created so many darn formulae that "Euler's formula" is ambiguous.

    7. Re:correction by Anonymous Coward · · Score: 5, Funny

      Too bad my mathematical abilities don't reach beyond spelling rude words on calculators held upside-down.

      Oh well. 5318008.

    8. Re:correction by Anonymous Coward · · Score: 0

      I had a Physics professor my first semester at college who never bothered to remember the formula for the Law of Cosines. So as he was doing proofs on the board, he redirived it from Euler's equation EVERY TIME.

    9. Re:correction by metlin · · Score: 0

      Nothing's geekier than a guy who writes down Euler's equation with a bunch of numbers and signs off as Scott.

      Beam anyone up lately, mayt?

    10. Re:correction by illuvata · · Score: 1

      Why would the fact that the /. submitter made a mistake disqualify the original?
      If you follow the links, you'll see that originally was used for Pi. Granted, it does look quite like n in some fonts, but you'd still think the submitter (or at least the editor) would have figured it out

    11. Re:correction by illuvata · · Score: 1

      And of course, I didn't preview, not realising /. wouldn't let me post special characters. Oh well, the character used for Pi in the originial was π not that I can figure out how to post it here. Anybody want to tell me?

    12. Re:correction by SamSim · · Score: 4, Interesting

      ...Which is in turn not to be confused with Euler's equation, which is V+F=E+2.

      Euler has a ridiculous amount of stuff named after him.

    13. Re:correction by b06r011 · · Score: 1
      i am not enough of a geek for this place.

      can anyone tell me (in a moderately short paragraph) why this is so important, or what it means...

      thanks

      (P.S. answers of "no, not even in a long paragraph" or "because" are welcome)

    14. Re:correction by joelethan · · Score: 1
      The glyph ISPi, not n.

      The article just uses the world's most illegible font. It got me for a minute. Try "View Source"

      I'd quote the source but the Pi renders on /. as "ð".

      /JE

    15. Re:correction by Anonymous Coward · · Score: 5, Funny
      Euler has a ridiculous amount of stuff named after him.

      A hockey team in Edmonton, Alberta...

    16. Re:correction by julesh · · Score: 1

      In itself, it isn't particularly important, other than the fact that it is a nice way to show a relationship between several mathematical constants that orginally arose in different fields.

      What is important is the key fact in its proof, which is that for any value 't', e^it = sin(t) + i*cos(t), which is a very important equality in the simplification of comlex formulae, and is therefore used frequently in diverse practical fields including electronic engineering.

    17. Re:correction by sgant · · Score: 4, Informative

      It was my mistake in the original posting. Not the article from Physics world, as I couldn't put in special characters.

      Talk about throwing the baby out with the bathwater!

      --

      "Leo Fender was in a 'state of grace' when he designed the Stratocaster." -- Paul Reed Smith
    18. Re:correction by miyako · · Score: 1

      this is the perfect reason to get a graphing calculator, most of which allow you to enter real text ;), think of the dirty word possibilities.

      --
      Famous Last Words: "hmm...wikipedia says it's edible"
    19. Re:correction by AuMatar · · Score: 4, Funny

      Ever wonder why they named 2.71... e? One guess.

      --
      I still have more fans than freaks. WTF is wrong with you people?
    20. Re:correction by cocotoni · · Score: 5, Funny

      As they say, in maths things are usually named after Euler, or the first person to discover them after Euler.

    21. Re:correction by Ford+Prefect · · Score: 1

      this is the perfect reason to get a graphing calculator, most of which allow you to enter real text ;), think of the dirty word possibilities.

      Graphics calculator, remember. Think of the dirty pictures!

      --
      Tedious Bloggy Stuff - hooray?
    22. Re:correction by Anonymous Coward · · Score: 3, Funny

      e for exponential?

    23. Re:correction by DigiShaman · · Score: 1

      Your forgetting 7734.

      --
      Life is not for the lazy.
    24. Re:correction by Grizzlysmit · · Score: 1
      Actually, isn't Euler's formula Exp[i*theta] = cos[theta] + i*sin[theta] ? and then substitute in the value of pi into theta, and the more famous result appears.
      Yep and that gets my vote, well except maybe Exp(i*theta) = cosh(i*theta) + sinh(i*theta), or how about c = 2*pi*r or A = pi * r^2, dammm I just love Equations ....
      --
      in my life God comes first.... but Linux is pretty high after that :-D
      Francis Smit
    25. Re:correction by Domini · · Score: 1

      Yup, I was happily playing with spring and damping equations in Applied Maths when I inadvertantly stumbled onto this identity. I had previously heard of it's existance and regarded it with awe, and was thus aware when my calculations went into that direction, and I promptly veered from my original solution to rather prove Euler's formula.

      For one thing it contains 'e' ... and as you can see from my e-mail address I have a whole site dedicated to it:

      http://e.co.za/

    26. Re:correction by b06r011 · · Score: 1
      thanks, that is now a little less unclear.

      maybe i should just study electronic engineering or something...

    27. Re:correction by SomeoneGotMyNick · · Score: 1

      And the word problems that created them.

      For example (participants modernized from early '70s version)

      142 Iraqis and 154 Saudis were fighting over 69 oil wells for 5 years. Who got the oil?

      Calculation:

      Key in 142 154 69 and multiply by 5

      Hit Equals and turn upside-down

    28. Re:correction by ForestGrump · · Score: 1

      71077345

      --
      Is it true that more people vote for the winner of American Idol, than vote for the president? -Ali G.
    29. Re:correction by aurelian · · Score: 1

      I remember reading in Gleick's biography of Richard Feynman that when he first learnt it (as a schoolboy) he called it 'the most amazing equation in all of math'.

    30. Re:correction by ForestGrump · · Score: 1

      And when you don't like someone
      Tell them to 7734206

      --
      Is it true that more people vote for the winner of American Idol, than vote for the president? -Ali G.
    31. Re:correction by Anonymous Coward · · Score: 0

      e is a number, not a function

    32. Re:correction by Anonymous Coward · · Score: 2, Funny

      I prefer Exp[j*theta] = cos[theta] + j*sin[theta], but then again, not everyone can be as cool as electronic engineers....

    33. Re:correction by oiarbovnb · · Score: 1

      saelloil? what the hell does that mean?

    34. Re:correction by loki1978 · · Score: 1
      Euler's equation is actually Exp[i*Pi] + 1 = 0 not Exp[i*n] +1 = 0 (unless they say n = Pi, which they don't).

      And your point was? The poster of the article used a Pi This is not an "n" but the greek symbol

      --
      According to prophecy
    35. Re:correction by ForestGrump · · Score: 0

      shell oil

      --
      Is it true that more people vote for the winner of American Idol, than vote for the president? -Ali G.
    36. Re:correction by provolt · · Score: 1

      Silly non-electrical engineers. Electrical Engineers know that sqrt(-1) is really "j" not "i". "i" is current.

      Why would you use the current variable for expressing complex numbers?

    37. Re:correction by oiarbovnb · · Score: 0

      aha! thanks

    38. Re:correction by ericspinder · · Score: 0

      ShELL OIL, 4 looks like a lower case 'H', for those of us getting way too old, the upside down calculator 'messages' provided way too much entertainment in study hall.

      --
      The grass is only greener, if you don't take care of your own lawn.
    39. Re:correction by saider · · Score: 2, Informative


      What is important is the key fact in its proof, which is that for any value 't', e^it = sin(t) + i*cos(t)


      If you have taken calc 1, this should be readable. Think of it this way.

      e^it, shows up a lot in engineering formulas, but can be a pain to work with. Being able to convert it to a sin/cosine formula makes it simpler because for certian values of t, sin() or cos() will be 1 or 0, and derivatives and integrals are fairly simple (eg. sin(x) d/dx = cos(x) ).

      --


      Remember, You are unique...just like everyone else.
    40. Re:correction by molasses · · Score: 1

      Agreed - in fact I've always thought rewritten this looks an even more beautiful equation:

      -e^(pi.i) = 1

      Four abstract concepts on the left surmising thousands of years of mathematical progress, create the most fundamental concept of all...

      Perhaps a little over dramatic, but elegant nonetheless!

    41. Re:correction by dreadfire · · Score: 0

      no correction really needed, its a pi symbol, not a n

    42. Re:correction by Enigma_Man · · Score: 3, Informative

      that is Pi up there, not n. It's a very small font, so it may look like an n, but it's actually a PI symbol...

      -Jesse

      --
      Nothing says "unprofessional job" like wrinkles in your duct tape.
    43. Re:correction by galt2112 · · Score: 1

      although it is a cool and elegant equation, the "5 most important numbers" is hooey.

      x + 1 = 0 -> x = -1 is the normalized form of this, and it contains neither 0 nor 1, so it only really contains 3 important numbers.

    44. Re:correction by dildo · · Score: 1

      I believe that it is a standing convention to name theorems or equations after the people who re-discovered them after Euler or Gauss (and sometimes one of the Lagranges) discovered them.

      Otherwise, it would be just downright confusing because these folks are responsible for so much important math -- everything would be named after them.

      Another euler equation: the fluid dynamics equation for non-compressible viscosity-free fluids.

      Can't recall what it is right now, it's been a long time since I took a class in continuum systems or fluid dynamics.

    45. Re:correction by tidewaterblues · · Score: 1

      Maybe I'm studip, but isn't it simplier and more elegant to write e^(i*pi) = -1. I mean, whose to say that -1 doesn't deserve a little math lovin'?

      --


      ...En að Besta Sem Guð Hefur Skapað Er Nýr Dagur
    46. Re:correction by Anonymous Coward · · Score: 1, Funny

      MOD THIS FUNNY

      i was falling off my chair.

    47. Re:correction by UnknowingFool · · Score: 4, Funny
      Too bad my mathematical abilities don't reach beyond spelling rude words on calculators held upside-down.

      Oh well. 5318008.

      Wouldn't it more appropriate to be: 55378008

      --
      Well, there's spam egg sausage and spam, that's not got much spam in it.
    48. Re:correction by jejones · · Score: 1

      That's de Moivre's theorem, but yes, you're right, though I don't know historically which came first.

    49. Re:correction by $calar · · Score: 1

      The difference between the two is that one is in the phasor domain and the other is in the time domain.

      You may write e^(j*theta) = cos(theta) + j*sin(theta)

      The phasor domain is very useful in electromagnetic theory because taking derivatives of e^x = e^x

    50. Re:correction by fshalor · · Score: 1

      Naivier Stokes Equations... And the Hadamand-Rybzynski equations. Together, you have fluid flow.

      And don't forget Reynolds, Nusselt and Grashoff!

      --
      -=fshalor ::this post not spellchecked. move along::
    51. Re:correction by TildeMan · · Score: 3, Informative

      Actually, it's not named after Euler, just by him. He did pick the name for the constant, but only picked 'e' because a, b, c, and d were already common elsewhere.

    52. Re:correction by Anonymous Coward · · Score: 0

      I is current, i is something else

    53. Re:correction by Speare · · Score: 1
      Euler has a ridiculous amount of stuff named after him.
      A hockey team in Edmonton, Alberta...

      And Houston Texas football, too.

      I find this funny because many people who are not maths fans are probably scratching their heads, expecting "Euler" to rhyme with "ruler." The mathematician's name is generally pronounced as "oiler." It wasn't until I worked for a bunch of engineering geeks that I put those together, even though I had read about Euler's works for years.

      --
      [ .sig file not found ]
    54. Re:correction by Anonymous Coward · · Score: 0

      ..Which is not to be confused with the other Euler equation d/dx(dF/dy')-dF/dy=0.

    55. Re:correction by Venner · · Score: 3, Funny

      Yep. There was a (somewhat tongue-in-cheek) footnote in one of my college math books that the tradition in mathematics was
      "...to name [things] after the second person who discovered them. Because Euler probably got there first."

      --
      A preposition is a terrible thing to end a sentence with.
    56. Re:correction by Anonymous Coward · · Score: 0

      Your Sharp may be guilty of cheating with some rounding. My HP48G tells me that 'e^(pi*i)+1' equals to -1.26676153736*10^-12*i :) Which is correct, given that calculator has value of pi stored with 12 vdigit precision. Along the way, it tells me the value of pi with the 24 digit precision when it calculates 'sin(pi)'. Can anyone figure out, how is that ;) I am curious about the Sharp nonanalytical interpretation of 'sin(pi)'.

    57. Re:correction by osmac · · Score: 1

      71349315

    58. Re:correction by SamSim · · Score: 2, Informative

      That would be the Euler-Lagrange equation.

    59. Re:correction by ralphclark · · Score: 2, Informative
      Actually,
      F+V = E+2
      is generally known as Euler's relation, probably to distinguish it from Euler's equation.
    60. Re:correction by Mixmaster+Bri · · Score: 1

      That n character you're referring to IS actually Pi.

    61. Re:correction by FuzzyBad-Mofo · · Score: 1

      But isn't current usually represented by a capital I, to differentiate it from the imaginary number i?

      Granted, it's been 10 years since I received my degree in electronics.. pretty fuzzy on anything outside of Ohm's law, which is permanently etched into my neural pathways. :)

    62. Re:correction by jar240 · · Score: 1

      Euler... Euler... Euler...... Anyone... Anyone... Anyone...

      --
      "You can drive out Nature with a pitchfork, but It always comes roaring back again." - Tom Waits
    63. Re:correction by garyrob · · Score: 1

      Ever since my high school math teacher showed this equation to me, I've had a problem with it because it is NOT elegant. It is artificially constructed to have both 1 and 0, when in fact it could be shortened to leave out 1 and have -1 on the right. THAT would be elegant, but it wouldn't be able to lay claim to having so many important numbers in it. It's a typical engineering case of a compromise between different aims. A good compromise, and an amazing formula, but still a compromise.

    64. Re:correction by admiralfrijole · · Score: 1
      i always learned it was e^(?i) + 1 = 0, becuase i comes after the real number whatever-you-call-it that accompanies it.

      you aren't really multiplying i and ? as much as you are saying the imaginary number whose square is -(?^2)

      or something like that...

      --
      e to the pi i plus one equals zero
    65. Re:correction by Anonymous Coward · · Score: 0

      Say it. You didn't RTFA!!

    66. Re:correction by kimota · · Score: 2, Funny

      Along similar lines, my favorite equation is best expressed as a question and answer:

      Q: What's the square root of 69?
      A: 8 something.

      Heh.

      --Kimota!

      --
      Who moderates the meta-moderators?
    67. Re:correction by Anonymous Coward · · Score: 1, Funny

      Euler's formula is what his mum fed him ...

    68. Re:correction by Mark+of+THE+CITY · · Score: 1

      SHELL OIL

      --
      The clearance system sounds logical. It is not. It is completely arbitrary. -- John Bolton
    69. Re:correction by ari_j · · Score: 2, Interesting

      Actually, the most important result, albeit not as famous, is that taking an irrational number to the power of an irrational imaginary number and adding a rational number gives you zero. For example, sqrt(2)^sqrt(-2) + 7 = 0.

    70. Re:correction by Anonymous Coward · · Score: 0

      Largely it's importance lies in its interestingness.

      i, pi, and e are three very important constants that all come from very different places in the math world. To see that they're all linked, and linked in such a relatively simple way, is usually a surprise to most people when they first see this equation.

    71. Re:correction by shoor · · Score: 2, Informative

      Actually, according to the wikipedia, Euler was not the first person to discover this, but rather, Roger Cotes. Though the wikipedia says he proved it in an obscured form. Search for "Euler's formula" in the wikipedia to confirm.

      --
      In theory, theory and practice are the same; in practice they're different. (Yogi Berra & A. Einstein)
    72. Re:correction by rrrrrrrrrrroar · · Score: 0, Troll

      You mean marius@e.co.za?

    73. Re:correction by squidfood · · Score: 2, Funny
      Actually, it's not named after Euler, just by him.

      Actually, it wasn't named by Euler, but by another man of the same name.

    74. Re:correction by achacha · · Score: 1

      If it wasn't for this equation, your cell phone wouldn't work.

      I know a lot of people whose cell phones work and they don't know this equation...

    75. Re:correction by Anonymous Coward · · Score: 0

      "I" is usually used for DC currents. While "i" is used for instantaneous AC currents by EEs and physics when talking about electronics.

    76. Re:correction by Anonymous Coward · · Score: 0

      That's not "n" - it is a character for pi that looks too similar to an "n".

    77. Re:correction by _anomaly_ · · Score: 1

      And Houston Texas football [team]... that doesn't exist anymore (the Oilers).
      They're now the Texans.

      --
      "I have no special gift, I am only passionately curious." - Albert Einstein
    78. Re:correction by Anonymous Coward · · Score: 0

      Actually, the Oilers became the Titans.
      The Texans are a new team that happens to
      be located in the Houston.

    79. Re:correction by joeygb · · Score: 1

      Well my favorite equation is something that a lot of /.ers may not understand. S(e^x) = f(u^n). Generally the integration symbol is used instead of S but you get the point....

    80. Re:correction by OwnedByTwoCats · · Score: 1

      Ummm, I don't think so. The Oilers moved to Tenessee (Nashville?), and became the Titans.

      The Houston Texans are an expansion team, much like the reconstituted Cleveland Browns. Only the "Oilers" name was so valuable the new team... chose something else.

    81. Re:correction by OwnedByTwoCats · · Score: 1

      Even-numbered Presidents of the USA from the 20th century (lets see how good my memory is):
      Clinton, Reagan, Ford, Johnson, Eisenhower, Roosevelt (FDR), Coolidge, Wilson, Roosevelt (Teddy).

      Odd-numbered Presidents of the USA:
      Bush, Bush, Carter, Nixon, Kennedy, Truman, Hoover, Harding, Taft, McKinley.

      Kennedy and Truman don't really belong on that list, and I don't think Ford and Johnson really belong on the first. Switch 'em and we're not too far from "effective" and "ineffective or disasterous".

    82. Re:correction by Sabu+mark · · Score: 1

      There was 1 girl who was 16 who 69'ed with 3 different guys, because she was really really...

      11669 * 3 =

      --

      What Would Jesus Do
      (for a Klondike bar)?
    83. Re:correction by Hawkeye477 · · Score: 1

      damn euler! I wish my cell phone didn't work, then work coudl not call me at 2 in the morning! :)

      --
      My Web Site - www.ocean-liners.com
    84. Re:correction by stephentyrone · · Score: 1

      the euler equations you have in mind are: rho * (dU/dt) = - grad p + rho*B (d rho/dt) = 0 div U = 0 with the flux of U across the boundary equal to zero (U.n = 0). U denotes the velocity field of the fluid, p is the pressure, rho the mass density.

    85. Re:correction by wildsurf · · Score: 1

      "...to name [things] after the second person who discovered them. Because Euler probably got there first."

      I had the wrenching experience of hearing the books-on-tape version of "The Fabric of the Cosmos", wherein Euler's name is repeatedly mispronounced "Yooler". What is this universe coming to, indeed.. (Also, Alan Guth's last name was mispronounced to rhyme with "fluff".)

      Incidentally, my favorite equation happens to be:

      2 + 2 = 5.

      (For sufficiently high values of 2.)

      --
      Weeks of coding saves hours of planning.
    86. Re:correction by stephentyrone · · Score: 1

      oops. preview before posting; silly me. that should have been:

      the euler equations you have in mind are:

      rho * (dU/dt) = - grad p + rho*B
      (d rho/dt) = 0
      div U = 0

      with the flux of U across the boundary equal to zero (U.n = 0).

      U denotes the velocity field of the fluid, p is the pressure, rho the mass density.

    87. Re:correction by Pharmboy · · Score: 1

      Euler's formula is what his mum fed him ...

      Euler's Formula is breast milk??

      --
      Tequila: It's not just for breakfast anymore!
    88. Re:correction by davidsyes · · Score: 1

      Man+Woman+Time very often = babies

      (Gene Roddenberry, from an interveiw from the late 60's or early 70's for the book "Star Trek", regarding mixed-gender deep-space assignments mixed with loneliness and physical cravings...)

      --
      Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
    89. Re:correction by Compenguin · · Score: 1

      I copied and pased that into the power toy calculator and it gave me sqrt(2)^sqrt(-2) + 7 = 7.8822721067610921828672489970121 + 0.47073976848291026594409863220197i

    90. Re:correction by Anonymous Coward · · Score: 0

      What is this i? You mean j, right?

    91. Re:correction by Mailleman · · Score: 1

      You better believe it. i is for wusses.

    92. Re:correction by Anonymous Coward · · Score: 0
      actually Exp[i*Pi] + 1 = 0 not Exp[i*n] +1 = 0 (unless they say n = Pi, which they don't).

      There is no "n" there; look again. You need to view the article using a browser having a better font. The equation is written there as:
      e<sup>i&#960; + 1 = 0.
      Unicode character 960 = 0x3C0 = Greek letter pi.

    93. Re:correction by taitertot · · Score: 1
      The Euler equations in fluid mechanics are for inviscid flow (no viscosity). There is no requirement for incompressibility. In fact, the most common use of these Euler equations is for computation of compressible flows (that don't involve or aim to resolve boundary layers).

      The relative importance of viscosity in a flow is indicated by the dimensionless quantity Reynolds number

      Re = rho*U*L/mu

      where rho is the fluid density, U is the characteristic flow speed, L is the characteristic length scale, and mu is the fluid viscosity. A large Reynolds number indicates that viscous forces are less significant than other forces. One way to achieve large Reynolds number is through high flow speeds, which can also lead to a large Mach number (generally, flows with Mach number > 0.3 are considered compressible).

    94. Re:correction by taitertot · · Score: 1
      rho * (dU/dt) = - grad p + rho*B
      (d rho/dt) = 0
      div U = 0

      The second and third equations in this list are not exactly part of the Euler equations in fluid mechanics. The first equation is the proper momentum equation if p is pressure and B is a body force, but the proper continuity (conservation of mass) equation is

      div(rho*U) = 0.

      This is more general as it allows for compressible fluids. The second equation above is an incompressiblity requirement, which combined with the more general continuity equation yields the third equation above.

    95. Re:correction by miltimj · · Score: 1

      Your target audience for this comment are people who are interested in favorite mathematical equations, yet you feel the necessity to point out the definition of "exponentiation"?....

      --
      "Truth is not decided by majority vote" consensus gentium -- Norman Geisler
    96. Re:correction by ari_j · · Score: 1

      You're either really gullible or have an even drier sense of humor than I do. Here's a test to find out which: Blame Microsoft, obviously the Power Toy calculator is innacurate. You need to use a TI-85.

    97. Re:correction by Funny+Bong · · Score: 1

      I don't think this equation enables my cell phone to work. Maybe it makes it a little easier to design it, but we could represent all of our signal values and other quantities without using this formula, or all complex exponents.

    98. Re:correction by Anonymous Coward · · Score: 0
      My favorite:

      There was 1 girl, she was 16, she did 69 3 times and what was she?: (11669*3) = 35,007

    99. Re:correction by batkiwi · · Score: 1

      I thought the exact same thing as you, but in the article on physics world they put an "n".

      For once the blurb got it right, and the article got it wrong. What's next, MS linux? Cats and dogs dancing together?

    100. Re:correction by Anonymous Coward · · Score: 0


      The difference between the two is that one is in the phasor domain and the other is in the time domain.

      You may write e^(j*theta) = cos(theta) + j*sin(theta)

      The phasor domain is very useful in electromagnetic theory because taking derivatives of e^x = e^x


      Ugh..
      Ok, english is not my first language, but this sounds like a wrong use of domain. The two functions are not in different domains, because they are equivalent. e^(i*theta) is the *exact* same theta as cos(theta)+j*sin(theta). This isn't something like an integral transform. If theta is in the "time" domain in one equation, it is in the "time" domain of the other equation.

      And d/dx e^x=e^x is not really why it's useful, because d/dx cos(x) + j*sin(x) = -sin(x) + j*cos(x). Which isn't terribly remarkable.

      The identity is remarkable because it connect the cyclic trigonometric (oscillations in physics) functions to vector analysis in the complex domain. Which makes a lot of analysis and representation in very simple and elegant (the results of which can be applied by even a high school student in a Physics or Electrical Engineering class).

    101. Re:correction by Anonymous Coward · · Score: 0

      Could someone give me a hint to the underlying joke? I probably would appreciate it, but I don't fucking get it. Does the result display a naked woman in ASCII art on your TI-85 or something? (I use an HP)

    102. Re:correction by Guignol · · Score: 1

      Those are the Bernouilli equations,
      Euler ones do deal with compressibility of fluids

    103. Re:correction by Anonymous Coward · · Score: 0

      SO does Dalton: Dalton's atomic theory, Dalton's Law of Partial Pressure etc... He was an amazing scientist. Do you agree?

    104. Re:correction by JasontheMason · · Score: 1
      That's funny.... the equation shows up as Exp[i*Pi] + 1 = 0 on my screen. Maybe it got edited or something.

      JtM

      --
      "Ad infinitem et ultra!" - Buzz Lightyear
    105. Re:correction by LauraScudder · · Score: 1

      Then it must be that Cauchy and Riemann got to everything in complex second, cause they sure as hell had everything but Euler's formula named after them.

    106. Re:correction by stephentyrone · · Score: 1

      if you read the parent comment, he was referring specifically to the euler equations for incompressible fluids.

      you're correct in noting that there is the more general set, but that's not what the parent was talking about.

    107. Re:correction by fingerfucker · · Score: 1

      It's 7734209, not 7734206.

    108. Re:correction by Wolfrider · · Score: 1

      > Euler's Formula is breast milk??

      ...and Soylent Green is PEOPLE!!!
      :b

      --
      .
      == WolfriderV6 == I'm willing to admit that *I just might* be wrong... Are you??
    109. Re:correction by _anomaly_ · · Score: 1

      Exactly.
      The parent to my original post said "houston football". Houston football no longer has anything to do with the "Oilers", they're now the Texans. Whether the original Oilers team was moved to Nashville or they were dissolved is beside the point.

      --
      "I have no special gift, I am only passionately curious." - Albert Einstein
    110. Re:correction by taitertot · · Score: 1

      I did read the parent comment, and I was correcting the parent's error. In fluid mechanics, the Euler equations specifically refer to the inviscid momentum equations (it's a vector equation, so it's really three equations, hence the plural). Whether the fluid is compressible or not enters through conservation of mass, which is seperate from the Euler equations but is used with them to solve specific problems.

    111. Re:correction by taitertot · · Score: 1

      I forgot one thing. The first equation

      rho * (dU/dt) = - grad p + rho*B

      has a small notation error. It should be written

      rho * (DU/Dt) = - grad p + rho*B

      with a convective derivative, where

      D()/Dt = d()/dt + u.grad()

    112. Re:correction by taitertot · · Score: 1

      The Bernoulii equation relates pressure and energy on a streamline, the Euler equations express the conservation of momentum for an inviscid fluid.

      See http://scienceworld.wolfram.com/physics/EulersEqua tionofInviscidMotion.html

    113. Re:correction by Keith+McClary · · Score: 1

      By "effective" do you you mean they started wars?

    114. Re:correction by Keith+McClary · · Score: 1

      There was 1 girl who was 16 who 69'ed with 3 different guys, because she was really really...

      11669 * 3 =


      1.588915931E12 ?

    115. Re:correction by Ford+Prefect · · Score: 1

      Your target audience for this comment are people who are interested in favorite mathematical equations, yet you feel the necessity to point out the definition of "exponentiation"?....

      Given that my post spawned a discussion about typing rude words into calculators, I think the definition may have been a good idea after all... ;-)

      --
      Tedious Bloggy Stuff - hooray?
    116. Re:correction by schematix · · Score: 1
      Beam anyone up lately, mayt?

      *begin sarcasm* Never heard that one before! *end sarcasm*

      --
      Scott
    117. Re:correction by schematix · · Score: 1

      For those of you making the comment that it is a "Pi" and not an "n", you are now correct. When the article was originally posted there was an n instead of Pi and it has since been fixed.

      --
      Scott
    118. Re:correction by atomm1024 · · Score: 1

      Yeah, this article is full of inaccuracies. Just look at this:

      from the comic-shop-guy's-revenge dept.
      It's Comic Book Guy, not Comic Shop Guy! Those ignorant fools.

      --
      Signature.
  2. sum of cubes by themusicgod1 · · Score: 4, Interesting

    a^3+b^3 = (a+b)(a^2-ab+b^2)
    first proof, that i'd seen at least, of the existance of negative numbers.

    --
    GENERATION 26: The first time you see this, copy it into your sig on any forum and add 1 to the generation.
    1. Re:sum of cubes by mikeage · · Score: 1

      Does the expression 0-1 prove there's a negative number?

      --
      -- Is "Sig" copyrighted by www.sig.com?
    2. Re:sum of cubes by themusicgod1 · · Score: 5, Interesting

      I mean, you're right it does. But man, was I skeptical.

      I say, that until I saw the sum of cubes I internally denied the existance of negative numbers. I mean I could work with them and all, I just didn't believe in them. If you deny the existance of negative numbers, you cannot have an expression 0-1, because -1 is meaningless, so therefor the result is meaningless. It's circular reasoning, and this is why[according to my youthful very non-standard way of thinking of things]:

      there is a number -1
      there is a number 0
      if you have two numbers, there is a third number which represents their sum. :.
      there is a number -1 + 0

      if there is a number -1 + 0 there must be a class of numbers known as negative numbers
      [the direction you were going in?]
      but if you cannot prove there is a number -1 + 0, you cannot even get that far.

      a^3+b^3 = (a+b)(a^2 - ab + b^2 ), on the other hand, shows quite clearly that no matter what numbers a and b you pick, you end up, in your equation, with a negative number.

      --
      GENERATION 26: The first time you see this, copy it into your sig on any forum and add 1 to the generation.
    3. Re:sum of cubes by mikeage · · Score: 1

      Is it correct to say, though, that 0-1 assumes the existance of -1? I.e., it's true that it's the same as 0+(-1), but that has to come after the existance. Doesn't the concept of subtraction automatically imply negative numbers?

      --
      -- Is "Sig" copyrighted by www.sig.com?
    4. Re:sum of cubes by Anonymous Coward · · Score: 0

      I'm sorry but I don't get your point... If you say that because of the fact that there is "- ab" in your equation you always have a negative number in it, if I take "a-a = 0" then you will also always have a negative number in your equation. It seems like saying, because they say god exists in the bible, this imply it exists because you will always hav it in any bible. Maybe I'm totally wrong or confused, so I'd like an elaborated explanation on how you can prove the existance of negative numbers based on the equation you showed. Tnak you!

    5. Re:sum of cubes by themusicgod1 · · Score: 2, Interesting

      ok[still grappling as to how exactly to reply to the earlier reply. it much more specifically hits at the critical point here; that systems of knowledge can be expressed as different sets of axioms, if expressable as axioms at all; and while my axioms may begin with additive inverses before subtraction, you may be able to go the other way, although I think it would be much less elegant. Stranger harmonies have erupted in mathematics than that, however... ]

      a-a=0, is not totally far off. Comutativity even less so(a-a+b+a=a+b+a-a etc). I think it is weaker, because it assumes that additive inverses/negative numbers exist. if -a doesn't exist, then a-a does not equal zero, since by definition there is no a-a.
      The suggestion that this is similar to proving god's existance via god's existance *in the bible* isn't really appropriate, as I do pull from two positive numbers, a negative number. Perhaps a similar argument involving god may turn out to be descartes';
      nothing can be created by something less perfect than it is. something [known as i] exists therefor something perfect exists, [by induction]. you start the argument with not-god, and you end with god. sure there's probably plenty wrong with that argument, but it doesn't fail in the kind of way that a-a=0 does; that you can simply define a-a=0 and be done with it; but you cannot define away the sum of two cubes, at least without doing a lot of damage.
      ie


      1^3 + 2^3
      1 + 8
      9
      (3)(3)
      (1+2)(3)
      (1+2)(1-2+4)

      OK so nothing really spectacular happens on the last step here. But I think that negative numbers, in this view, become something of a property of regular, positive numbers. That they only exist insofar as relationships not between positive numbers and zero[ie, the standard a-a=0 view], but between different collections of items. There is a ratio which is *always* upheld, whether or not negative numbers exist. but if -ab is not negative, (ie, it is some ab instead) then the numbers a and b must have been subtracted. etc.

      where I think this thread will actually get interesting is here:

      god exists in the bible.
      therefor god exists.
      It is the nature of god in which my opinion may differ with others; Whereas some believe him to be, well, whatever they believe him to be, I will suggest that god is the collection of ideas, motivations and actions of those who believe in it, much the same as I am the sum of my actions, God is practically everywhere, and the effects of god can be long reaching on an almost unimaginable scale...at least for my imagination. How can you argue against this? if you believe that god has X nature, I too believe that god has X nature, in the amount that your opinion matters. if your opinion matters greatly, for some reason, X is relatively greatly true. I say.

      damn am I ever hungry. I'm going for some KD.

      --
      GENERATION 26: The first time you see this, copy it into your sig on any forum and add 1 to the generation.
    6. Re:sum of cubes by krumms · · Score: 1, Funny

      I say, that until I saw the sum of cubes I internally denied the existance of negative numbers.

      Okay I know this is slashdot and there's been some pretty nerdy posts before, but jesus

    7. Re:sum of cubes by Entropy · · Score: 1
      a^3+b^3 = (a+b)(a^2 - ab + b^2 ), on the other hand, shows quite clearly that no matter what numbers a and b you pick, you end up, in your equation, with a negative number.


      I pick zero, and, um ... zero.

      I see no negatives anywhere ...
      --
      The sea changes color, but the sea does not change.
    8. Re:sum of cubes by Anonymous Coward · · Score: 0

      This proves the existence of negative numbers in the same way that (1+i)(1-i) = 2 proves the existence of imaginary numbers. I.e. it does not. Unless you have additive inverses or subtraction a^2-ab+b^2 does not parse.

      Additive inverses and subtraction are defined for integers and real numbers, but not for p-adic numbers .

    9. Re:sum of cubes by Kippesoep · · Score: 5, Funny

      I wish I could deny the existence of negative numbers. My bank, on the other hand, insists that is how much money I have...

    10. Re:sum of cubes by potifar · · Score: 1

      Eh? The p-adic numbers form a field (well, one field for every p), so in particular they are an abelian group under addition, which means that additive inverses (and subtraction) exist.

    11. Re:sum of cubes by Anonymous Coward · · Score: 0

      Indeed they do. What I should have said is that positive and negative numbers can only be defined when there is no square root of -1.

    12. Re:sum of cubes by Harbinjer · · Score: 1

      I started to believe in negative numbers as soon as I asked my parents, " what's 7-8?" and poof! I realized that negative numbers existed. I was in second grade at the time.

    13. Re:sum of cubes by Anonymous Coward · · Score: 0

      A mathematician could then probably conclude that 0 is not a number....or is it?

    14. Re:sum of cubes by SimonShine · · Score: 1

      I am willing to acknowledge that money exist just as much as negative numbers, but not as the apple in my hand. If I lack an apple in my hand, it was never there in the first place unless we compare now with a possible past, which is again quite non-existent.

      --
      Take off every 'ZIG' !!
    15. Re:sum of cubes by Anonymous Coward · · Score: 0

      Yes?

    16. Re:sum of cubes by John+Courtland · · Score: 1

      Basically, denying negative numbers denies that there is a solution to any problem x+y=0. Perhaps negative numbers don't 'exist' per se, but more as an inverse magnitude of a positive number. Similar to the notion that all acceleration is positive to the object being accelerated, but from a different frame of reference, it could appear negative.

      --
      Slashdot is proof that Sturgeon's Law applies to mankind.
    17. Re:sum of cubes by Eric119 · · Score: 1

      I think the whole question of whether negative numbers are real is misguided. Negative numbers exist, by definition. They're defined because they're useful. Just like positive numbers are defined because they're also useful.

      People ask questions like "Are negative numbers real?", "Are complex numbers real?", "Is four-dimensional geometry real?" etc., because they're harder to intuitively grasp. But in the end they're no more abstract than positive numbers, it's just harder to map them to concepts in the real world.

      Essentially, if we can define a mathematical concept to exist without contradicting ourselves, exists. Thus, given, "For all x, there exists a number -x such that x + (-x) = 0", we have now defined a kind of number (additive inverse, or negative).

    18. Re:sum of cubes by Anonymous Coward · · Score: 0

      Hmmm.... Well... Actually, there is an axiom that states that, for every number 'a', theres another number '-a' so that: a + (-a) == 0
      That's an axiom for the real numbers. (English is not my native language, sorry)

    19. Re:sum of cubes by Anonymous Coward · · Score: 0

      Now if only there was a proof for the existance of positive numbers.

    20. Re:sum of cubes by Anonymous Coward · · Score: 0

      woah, there, music man -- what about the good, old additive identity?

      let 'n' be an element of a ring ['R'] with additive identity, then there exists a number 'a', also a member of 'R' such that 'n' + 'a' = 0['R']

      which gives us the result that 'a' = (-1)['R'] x 'n'

      (it's easier, and simpler, not to mention more intuitively obvious, to use mathmatical shorthand, rather than plaintext, but you work with what you have)

      when i was teaching basic algebra classes, i would use everything from a number line to the concept of profit and loss to give the students a handle on the concept of negative numbers - reserving the ring theory for more abstract classes (e.g. Abstract Algebra &al)

    21. Re:sum of cubes by Nate+Eldredge · · Score: 1

      (Caution, math humor ahead)

      nothing can be created by something less perfect than it is. something [known as i] exists therefor something perfect exists, [by induction]. you start the argument with not-god, and you end with god.

      Well, you can't quite use induction, because the chain of increasingly perfect things between i and god may not be finite. So even if you can always find something more perfect, you may not ever reach the most perfect element in a finite number of steps. Moreover, it is not the case that, given any pair of things, one of them created the other. So the axiom (if a created b, then a is more perfect than b) doesn't give us that "more perfect than" is a total ordering, only a partial ordering. So there isn't necessarily a single chain to follow.

      However, we can still get the conclusion if we're willing to assume a little more. Suppose that any set of things which is totally ordered under "more perfect than" (i.e. given any pair of elements, one is known to be more perfect than the other) has a "most perfect" element. This seems like a reasonable assumption: when you do have a chain of things which created one another, it is plausible that one may have (indirectly) created all the others. In this case, we can apply Zorn's lemma (equivalent to the axiom of choice). Now the set of all things has a most perfect element, which we may call god.

      So the axiom of choice implies the existence of God!

      For future research: prove the converse. Then the axiom of choice will be equivalent to the existence of God. That should add a little excitement to the dry field of set theory. It will also reduce the mathematical question of whether to accept the axiom to the corresponding theological question, and vice versa, so you can answer both at once.

      Your other argument has a little problem, though. : "god is the collection of ideas, motivations and actions of those who believe in it". Presumably God believes in God, and has an idea of God, and therefore God is contained in Itself. When you allow sets to contain themselves, you run straight into Russell's paradox (consider the set of all sets not containing themselves: does it contain itself?) There's a reason why the Z-F axioms of set theory forbid this. So that's probably not a good definition for God. It also doesn't imply uniqueness. (If distinct sets of people believe in distinct Gods, then such distinct Gods will exist. And some of them, perhaps even all, may be quite small).

      What is KD, anyhow?

    22. Re:sum of cubes by Anonymous Coward · · Score: 0

      I use a credit union, you insensitive clod.

    23. Re:sum of cubes by slothman32 · · Score: 1

      When I was that young, possibly 1st grade though, my teacher said you couldn't do that. "It doesn't make any sense and will be ignored," as a paraphrase she said. Of course I knew otherwise but that would just confuse here even if not the other students. But then what do I know. In kindergarden I learned 'w' is a vowel. I never knew it was 'til I learned the 2 words a couple years ago.

      --
      Why don't you guys have friends or journals?
    24. Re:sum of cubes by arodland · · Score: 1

      I'm not sure. If you look at it formalistically, then addition is fundamental, and subtraction only exists because negative numbers do. But if you look at it more concretely, then "take away" is just as fundamental to us as "add to", because it's really all just moving things around (conservation of mass and such). So addition and subtraction are just as natural to us by the time we get to thinking more formally about math, and then negative numbers are these things that somehow represent a quantity "subtracted". Which tends to be really confusing. I spent a long time, when I was younger, trying to figure out why addition commutes when subtraction doesn't; I knew it was true, but I couldn't figure out what the difference was. But a-b = a+(-b) explains it perfectly.

    25. Re:sum of cubes by heffrey · · Score: 1

      I don't think that this proves that negative numbers exist. In fact I'm not really sure numbers exist at all.

      I think what happens is that we write down some mathematical axioms and then prove some theorems that we find useful. The theorems are only ever true if the axioms are true. And axioms are just what we choose. Of course we choose ones which lead to theorems which describe our world well.

      So I would never say that negative numbers exist, just that they are extremely useful.

    26. Re:sum of cubes by Anonymous Coward · · Score: 0

      the thing is that subtraction does not necessarily imply negative numbers. If you are working in hte natural number set you can still subtract, it is just that you cannot subtract any two numbers that you want and get a meaningful answer.
      ie the natural numbers have no negatives
      but you can still say 4-1=3 you are fine and just have defined a operator - that gives you this relation however if you take 1-4=? this becomes undefined for the system you are working in because negative numbers do not exist for your set.

    27. Re:sum of cubes by geekpolitico · · Score: 1

      One of my friends was an avid MUD'er (remember those), and he used to log onto to various muds, go to the bank and "withdraw -1000000." More often than not he would end up with 1000000 coins on his character. If only ATM's allowed me to do that.

    28. Re:sum of cubes by jonadab · · Score: 1

      there is a number -1
      there is a number 0
      if you have two numbers, there is a third number which represents their sum. :.
      there is a number -1 + 0

      > if you cannot prove there is a number -1 + 0, you cannot even get that far.

      That's because you're approaching it from the wrong direction. You can't use
      the existence of negative numbers to prove the existence of negative numbers.
      You need to drop subtraction and -1 from your logic and build the demonstration
      on just addition and positive integers. Start by demonstrating zero, and
      proceed to negative numbers along the same lines.

      --
      Cut that out, or I will ship you to Norilsk in a box.
    29. Re:sum of cubes by plaa · · Score: 1

      As some others have already noted, this does not prove anything. Negative numbers are only available through definition, if they are defined at all. However, there's no need to have them (then you just can't use the "normal" math you learn at school).

      The "normal" axioms used in everyday math are the following (not necessarily in that order - and please forgive me if some of the translations are wrong):

      I. Calculation laws

      We assume there is an operation + and *, which operate on elements of some set S, and the result of which is in the set S.

      1. Commutativity: a+b=b+a, a*b=b*a
      2. Associativity: a+(b+c)=(a+b)+c, a*(b*c)=(a*b)*c
      3. Distributive law: a*(b+c)=a*b+a*c

      These define a few basic properties about the operations + and *, and how they work together. We still have no idea what the objects a, b and c are on which they operate.

      4. Zero: There exists an element 0 such that 0+a=a for all a.
      5. One: There exists an element 1 such that 1*a=a for all a.

      Now we have two defined elements in the set S. Actually, though rarely mentioned, we need additionally to assume that 0 is not 1, because the set {0} with 0=1 would fulfill all the requirements above and below.

      Now we can ask what is 1+1? We could define 1+1=1, and get a Boolean algebra. Or we might have 1+1=2 and 2+1=0, which would be summing mod 3.

      6. Opposite number: For every a there is an x such that a+x=0.

      This still doesn't require "negative" numbers. In the latter example above, the opposite number of 1 would be 2, since (by definition) 2+1=0.

      7. Inverse number: For every a not equal to 0 there is an x such that a*x=1.

      In the case of natural numbers, this would force us to adopt rational numbers, but otherwise it's still not necessary. In the above example the inverse number of 1 is 1 because 1*1=1 and the inverse of 2 is 2, since 2*2 = (1+1)*2 = 1*2+1*2 = 2+2 = (1+1)+2 = 1+(1+2) = 1+0 = 1.

      II. Ordering relations

      For every a, b and c holds:
      1. either a<b, a=b or a>b
      2. if a<b and b<c then a<c
      3. a<b is equivalent with a+c<b+c
      4. if a>0 and b>0 then a*b>0

      This requires us to expand our number set. The above example would be contradicting at least axiom II.3, since, if we say that 0<1<2, then 2=1+1<2+1=0, which is a contradiction.

      At this point axioms I.1-I.5 make necessary all natural numbers (0, 1, 2, ...), I.6 makes negative numbers necessary, and I.7 makes rational numbers necessary. But what about real numbers?

      They are clinched in a very interesting way (which can also be formulated in different ways):

      III. Completeness axiom

      1. Every bounded set has a smallest upper bound and a largest lower bound.

      Take, for instance, the set T={1,3,7}. In this case all the numbers 7, 15 and 543632 are upper bounds for the set (because all elements of the set are less or equal to them), but 7 is the smallest possible upper bound.

      Then take the set T={x|x^2<2} (the set of all numbers for which x^2<2). It's clear that it is bounded, but if you take any rational q for an upper limit, you have q^2>2, and so you can find a smaller q', q^2>q'^2>2. Therefore the lowest upper bound cannot be a rational number, and we must "fill in" the gaps left by rational number with the irrational numbers.

      That's a short preview of how real numbers are (or can be - there are alternative ways) defined. The point is that only after you pick your axioms can you really say what you have or have not. You don't need to pick the axioms above - for instance congruence calculations (calculations mod some integer m) are very useful - and in fact your equation a^3+b^3 = (a+b)(a^2-ab+b^2) is true also in this case, even though there aren't any explicit "negative" numbers defined!

      [Note that there may be minute errors in the above - it's been several years since I played with the axioms last time.]

      --

      I doubt, therefore I may be.
  3. V=IR by oddbudman · · Score: 5, Interesting

    Gotta Love V=IR. Works pretty well, I use it daily, well that and P=VI.

    1. Re:V=IR by panurge · · Score: 1

      Obviously another person who never uses AC.

      --
      Panurge has posted for the last time. Thanks for the positive moderations.
    2. Re:V=IR by infolib · · Score: 1
      Except it's only true within certain limits - if you look at nanostructures they often have I/V characteristics that are not linear at all. It isn't really useful for superconductors either.

      Even if you use V=IR for a filament bulb, it might not be correct, as the temperature changes when you apply more voltage, leading to a different resistivity of the filament, so R is not a constant. (Of course you could set up your experiment to keep the filament at constant temperature, but that's not really realistic).

      In short, this equation is very important for lots of technology, but it's really not a "deep" statement on its own - it's merely a consequence of underlying laws of nature. (Maxwell equations, quantum mechanics) and then only under special circumstances. Therefore I would prefer something like the least action principle, Schrödingers equation, or something like that. The ergodicity principle is extremely full of beauty and consequence too, but I haven't seen it stated as an equation.

      --
      Any sufficiently advanced libertarian utopia is indistinguishable from government.
    3. Re:V=IR by Anonymous Coward · · Score: 0
      Even if you use V=IR for a filament bulb, it might not be correct, as the temperature changes when you apply more voltage, leading to a different resistivity of the filament, so R is not a constant.

      You have completely missed the point.

      V=IR. R changing as a result of temperature dependence is an indepdenent operation. As the resistance changes, "I" will change for a fixed voltage.. That's what V=IR is all about.

    4. Re:V=IR by Technician · · Score: 3, Informative

      Obviously another person who never uses AC.


      What's wrong with AC. R is resistance, not impedance or reactance. If you add reactance to the equasion, then you need a new formula, but that equasion has current, voltage and resistance. The formula holds true. Don't read in inductance and capacatance where there isn't any.

      This is Ohm's law, not Kirkoff's law.

      For formulas that include reactive components, they are listed here;

      http://www.tpub.com/neets/book2/6.htm

      --
      The truth shall set you free!
    5. Re:V=IR by AuMatar · · Score: 3, Informative

      You're making a big mistake- you're assuming R has to be a constant. It doesn't need to be. R is the resistance, which can be a formula. Actually, it is a formula- R=l*psi/A where l is length, A is cross sectional area, and psi is the resistivity of the substance (which again, can be a formula that takes in temperature, or may be a constant for given material and temperature).

      --
      I still have more fans than freaks. WTF is wrong with you people?
    6. Re:V=IR by djdead · · Score: 5, Interesting

      When I was taking physics for the first time in high school, a EE from MIT taught me the following:

      twinkle twinkle little star
      power equals I squared R

      I remembered it.

      --
      -1: flamebait should really be -1: inciteful
    7. Re:V=IR by Anonymous Coward · · Score: 0

      You must have a demanding job

    8. Re:V=IR by klaasvakie · · Score: 2, Informative

      Obviously another person who never uses AC

      At any moment in time the equation V=IR holds for any circuit (yes, even AC circuits). It is just that when you have caps and inductors in your AC circuit their impedance changes all the time, making the V=IR equation less usefull.
      When one only has resistive impedance elements it is possible to use V=IR for AC circuits by replacing V with Vrms, and I with Irms, the Root-Mean-Square value of the AC voltage or current, giving Vrms = Irms*R.

      --
      # ssh -l neo the_matrix; killall -9 agent_smith
    9. Re:V=IR by basingwerk · · Score: 1

      Even more interesting is the compound interest equation : (P = C (1 + r/n)) ** nt

      --
      I stole this .sig
    10. Re:V=IR by infolib · · Score: 1
      You're making a big mistake- you're assuming R has to be a constant.

      I assume R has to be independent of V and I. Otherwise Ohm's law doesn't add any information, just a redundant symbol (R). When it comes to nanostructures Ohm's law is definitely out the window - have a look at figure 1 (bottom left) showing the Coulomb blockade effect. Try to fit a straight line to the jagged graph at the bottom :-)

      In the bulb example R is in principle independent of V, but in most practical situations it would depend indirectly on V as described. It is still clear that Ohm's law is

      1. Valid in a limited regime
      2. Not a fundamental law of nature
      3. Extremely useful.
      Given point 1. and 2. I still think Ohm's law ranks poorly as the greatest equation of all time, but then again I'm not an electrical engineer.
      --
      Any sufficiently advanced libertarian utopia is indistinguishable from government.
    11. Re:V=IR by infolib · · Score: 1
      You have completely missed the point.

      No I didn't. I explicitly adressed it. "R changing as a result of temperature dependence" is not "an indepdenent operation" if temperature depends on voltage. Of course it need not do, but it would in the simple experimental setup described.

      If R changes with V (as it does for nanostructures, and in the simple bulb setup) all Ohm's law really states is that "there exists a number R=V/I" but we already knew that for any I not equal zero. The practicality of Ohm's law is that R is in many practical cases independent of V and I (or has some well-known dependency), but that's by no means a fundamental law of nature.

      --
      Any sufficiently advanced libertarian utopia is indistinguishable from government.
    12. Re:V=IR by Hatta · · Score: 2, Interesting

      I happen to like the Gibbs free energy equation:

      delta G = delta H - T(delta S)

      This equation balances the contributions of entropy (S) and enthalpy (H) and tells you if a given reaction is energetically favorable. delta H is the total energy in a reaction, while T(delta S) is the energy unavailable for work. A quick rearrangment shows that delta G is the energy available for doing work.

      I'm also fond of Shannons juggling theorem.

      --
      Give me Classic Slashdot or give me death!
    13. Re:V=IR by Ignignot · · Score: 1

      I heard from the head of our Electrical Engineering department that Ohm, who discovered Ohm's law (V = IR), was fired from his university position because they felt that his equation was too obvious and that he wasn't doing useful work. Then again the department head could have been wrong... he was getting on in his years.

      --
      I submitted this story last night, and it didn't get posted.
    14. Re:V=IR by CGP314 · · Score: 1

      And the second verse:


      Splishy splashy in the sea
      Power equals I times V


      -Colin

    15. Re:V=IR by Anonymous Coward · · Score: 0

      I came across another simpler way to remeber Ohm's law:

      Very = Important Rule
      [V] = [I] [R]

    16. Re:V=IR by Brandon30X · · Score: 1

      Of course Ohm's law can be derived from Maxwell's equations, which are my personal favorite. So complex but elegant. Now to find that elusive magnetic charge!

      --
      Quitters never win, Winners never quit, But those who never win and never quit are idiots.
    17. Re:V=IR by mekkab · · Score: 1

      Gotta love deriving V=IR from maxwell's equations (talk about mind blowing!)

      --
      In the future, I would want to not be isolated from my friends in the Space Station.
    18. Re:V=IR by Daniel+Dvorkin · · Score: 1

      Yep. It's particularly useful for showing creationists who make stupid arguments based on an incomplete understanding of the 2nd Law of Thermodynamics how wrong they are. Or, er, it would be, if they could be bothered to get the education to understand the equation at all ...

      --
      The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
    19. Re:V=IR by adam31 · · Score: 1
      Obviously another person who never uses AC.

      No Kidding! Damn karma whores. Euler does all the work and this guy gets a [+5 Interesting]. Shameless.

    20. Re:V=IR by Quantum+Jim · · Score: 4, Funny

      There was once a football player who was teetering on the edge of academic eligibility. To help the poor guy with his physics test, the coach told him:

      Remember this ryme, to get the power in a circuit:
      Twinkle twinkle little star,
      Power equals I squared R.

      Well the school day before the exam, the football player also had a big game. He tackled alot of people and had a really good day. However, the next day he failed his test! The coach couldn't understand, so he asked the player if he remembered the ryme. The football player said:

      Of course, coach:
      Twinkle twinkle star in the sky,
      Power equals R squared I!

      There's a moral in there somewhere. :-)

      --
      It is impossible to enjoy idling thoroughly unless one has plenty of work to do.
      - Jerome Klapka Jerome
    21. Re:V=IR by Galvatron · · Score: 1

      I remember a Mr. Boffo comic several years back titled "The dark side of mnemonics," and showed a guy sitting in a car thinking to himself "Now is it 'Red, red, go ahead,' or..."

      --
      "The question of whether a computer can think is no more interesting than that of whether a submarine can swim" -EWD
    22. Re:V=IR by winokungfu · · Score: 1
      Obviously another person who never uses AC.
      I know I'm not the only one who needed a minute to realize they weren't talking about checking "Post Anonymously".
    23. Re:V=IR by zhiwenchong · · Score: 1

      If you are a VI fan and an elecrical engineer, you can always express it this way:

      VI = Power

    24. Re:V=IR by a10t2 · · Score: 1

      Resistivity is generally written as rho, not psi.

    25. Re:V=IR by imagmast · · Score: 1

      I am surprised I had not seen Maxwells Field Equations mentioned. Of course they don't roll off your tongue (especially the integral versions), but they were significant in showing the relationship of light, electricity & magnatism. As I recall, it is written in the bible: Let there be "Maxwells Field Equations" & there was Light :)...

    26. Re:V=IR by jonadab · · Score: 1

      # ssh -l neo the_matrix; killall -9 agent_smith

      Have you ever tried to killall a program that's forking itself constantly?

      Doesn't work. You end up killing all the processes that were active at the
      time you started the killall, but there were others forked before you got
      them killed, so _those_ processes continue to fork off more.

      What you have to do is perl -e 'while(1){`killall -9 agent_smith`}'
      This geometrically reduces the number of offending processes each iteration,
      because it loops faster than the others can fork; you can then kill off your
      perl process easily once you're sure all the offending forking processes are
      all quite well and truly dead.

      --
      Cut that out, or I will ship you to Norilsk in a box.
    27. Re:V=IR by Anonymous Coward · · Score: 0

      Obviously another person who never uses AC

      Huh? Wha?... Who said my name?

    28. Re:V=IR by srleffler · · Score: 1

      Yes, but one also has to be careful when dealing with AC systems. For example, P=I*V is only true for instantaneous quantities in general. People often get into trouble by measuring the RMS voltage and current and assuming that the average power is equal to the product of the two. This is sometimes true, but not always.

    29. Re:V=IR by klaasvakie · · Score: 1

      I wrote that sig before the last matrix movie came out, thus I was unaware of the extreme forking abilities of the agent_smith program.

      Although your solution is correct if the agent_smith program is continually forking, the agent_smith program does not continually fork. It forks to fill available space and then stops. Killing a single instance after the agent_smith program has finished forking does not cause it to respawn (I cannot remember any of the agent_smiths in TM3 respawning after being zapped by neo - could be wrong though).
      SO if my .sig were to be run at a time when agent_smith has finished it's forking process it will still manage to get rid of all the instances of agent_smith

      But even if agent_smith forks constantly, you do agree that you cannot keep your while(1) running forever since that would be too much of a drain on neo and the system. And in that case, the moment you kill your perl script, the agent_smith program will be started from a cron job a few seconds later. So to solve the problem completely you have to killall -9 crond; killall -9 agent_smith; but killing crond will have catastrophic effects to the whole of the_matrix. So it is only a temporary solution anyway.

      --
      # ssh -l neo the_matrix; killall -9 agent_smith
    30. Re:V=IR by Technician · · Score: 1

      For example, P=I*V is only true for instantaneous quantities in general.

      For power use P=I*V*PF

      PF is power factor. It varies from 1 to 0. Values less than 1 are either capacitive or inductive. A value of 1 is resistive. Capacitive is when the current leads the voltage and inductive is when current lags voltage.

      --
      The truth shall set you free!
  4. Impressions of math equitations. by Anonymous Coward · · Score: 0

    1 + 1 = 11

    I was impressed by the technical background of it.

    1. Re:Impressions of math equitations. by Paster+Of+Muppets · · Score: 1, Funny
      No, 1 + 1 = 10...

      Waiting for everyone to switch their calculators to binary mode...

      --
      Due to lack of disk space this user has been discontinued
    2. Re:Impressions of math equitations. by Anonymous Coward · · Score: 0
      1 + 1 = 11

      Insufficiently geekazoid -- everyone knows 1 + 1 = 10.

    3. Re:Impressions of math equitations. by DarkDust · · Score: 1, Funny

      1 + 1 = 11

      There are 10 types of people: those who understand binary arithmetics and those who dont :-)

    4. Re:Impressions of math equitations. by LittleBigLui · · Score: 1
      1 + 1 = 11

      There are 10 types of people: those who understand binary arithmetics and those who dont :-)


      Except your arithmetics are unary (or at least "unique"), not binary.
      --
      Free as in mason.
    5. Re:Impressions of math equitations. by Anonymous Coward · · Score: 0

      And it's obvious to whom you belong... ;)

      Need I point out that 1+1=10 in binary?

    6. Re:Impressions of math equitations. by Frogbert · · Score: 1

      That equation is in base 1 you fool!

    7. Re:Impressions of math equitations. by Associate · · Score: 4, Funny

      There are 11 types of people:
      Those who understand binary
      Those that don't
      And those that think they do.

      --
      Someone hates these cans.
    8. Re:Impressions of math equitations. by rooijan · · Score: 1

      those who understand binary arithmetics and those who dont

      Would it be rude of me to point at that, in binary arithmetic at least, 1 + 1 = 10?

      --
      Daar is nie 'n lepel nie
    9. Re:Impressions of math equitations. by ZigMonty · · Score: 1

      Maybe they were using base 1?

    10. Re:Impressions of math equitations. by El_Muerte_TDS · · Score: 1

      Would base 1 just have 0. So:
      0+0=00

    11. Re:Impressions of math equitations. by notamac · · Score: 1

      Nah... he just overloaded '+' to mean concatenation...

    12. Re:Impressions of math equitations. by Anonymous Coward · · Score: 0

      nono.. in base-1 1+1=11 (or 0+0=00 if you write it like that..)

      In anything higher than base-2 1+1=2 though.. ;)

    13. Re:Impressions of math equitations. by ajs318 · · Score: 2, Interesting
      1 + 1 = 11? It does in Javascript.

      Suppose you have something like this (apologies for loss of indentation)
      function min_up() {
      if (document.theform.mins.value < 59) {
      document.theform.mins.value += 1;
      };
      };
      function min_down() {
      if (document.theform.mins.value > 0) {
      document.theform.mins.value -= 1;
      };
      };
      ...
      <form name="theform" method="post" action="<? echo $this_script?>">
      ...
      <input type="text" name="mins" value="<? echo date('i') ?>" />
      <a href="JavaScript:min_up()"><img src="gfx/uparrow.png" /></a>
      <a href="JavaScript:min_down()"><img src="gfx/downarrow.png" /></a>
      This is ripped off from a web application I once wrote. You should be able to modify the time by typing figures into the box or by using up and down arrows. What happens in practice is that adding 1 actually concatenates "1" on the end of the string, so you find that 1 + 1 = 11, and 11 + 1 = 111.

      This is what you get when you borrow one idea from Perl about how the computer should be able to work out from context whether or not something is a number or a string; and one from BASIC about re-using operators obviously out-of-context {strings cannot be added} to mean something different {such as concatenation}. The result, as they say, is a mess. For all practical purposes, JavaScript lets you subtract, multiply and divide numbers; but if you want to add, you'd better subtract a negative number.

      I mean, it's not freaking rocket science, is it? = is for telling, == is for asking. + is for adding, . is for joining strings. Sheesh!
      --
      Je fume. Tu fumes. Nous fûmes!
    14. Re:Impressions of math equitations. by LittleBigLui · · Score: 1

      or he combined it with that old "1+1=3 for large values of 1" joke.

      --
      Free as in mason.
    15. Re:Impressions of math equitations. by Anonymous Coward · · Score: 0

      In the words of Professor Frink
      Pi is exactly equal to 3

    16. Re:Impressions of math equitations. by zhenlin · · Score: 1

      1 + 1 = 11 = 101 = 1001 = 10001 = 100001 = ...

      For base 1.

    17. Re:Impressions of math equitations. by DarkDust · · Score: 1

      And it's obvious to whom you belong... ;)

      Need I point out that 1+1=10 in binary?

      Need I point out that I was quoting a comment that contained "1+1=11", to which I replied that there are 10 kind of people... ? Oh man...

    18. Re:Impressions of math equitations. by Anonymous Coward · · Score: 0

      There are 10 types of people:
      Those who understand trinary
      Those who dont
      And those who mix it up with binary.

    19. Re:Impressions of math equitations. by Anonymous Coward · · Score: 0

      Dude, it's isomorphic. Call it 1 or 0 or G or Gamma. It's the relation we care about.

    20. Re:Impressions of math equitations. by mark-t · · Score: 2, Informative
      For any number base n, there are n distinct symbols that can be used to represent the magnitude of that value. Any representation of a number with more than n distinct symbols in it cannot possibly be taken as a number in base n.

      In layman's terms, in base 1, 1+1=11, 11+1=111, 111+1=1111, and so on. This is consistent with the requirement that the number of symbols in a number represented in base n contains no more than n distinct symbols. But base 1 contains mathematical inconsistencies when representing non integers (or even the integer 0) which can't permit it to be acceptable as a valid base.

    21. Re:Impressions of math equitations. by Anonymous Coward · · Score: 0

      That's only 3.

    22. Re:Impressions of math equitations. by Nate+Eldredge · · Score: 1

      There are 11 types of people: those who can count in binary, and those who can't.

    23. Re:Impressions of math equitations. by rooijan · · Score: 1

      Sorry, it wasn't clear to any of us (or to me at least) that you were quoting someone, since your comment was over the +1 threshold and the parent clearly wasn't.

      The potential for a good set of humorous corrections has just evaporated. Ah well...

      --
      Daar is nie 'n lepel nie
  5. Take a guess.... by oneandoneis2 · · Score: 5, Funny
    Some of the equations mentioned were the simplistic 1+1=2 and Euler's equation, e^in + 1 = 0. What are some of your favorite equations?"

    Take a look at the username, and take a guess at mine :o)

    --
    So.. it has come to this
    1. Re:Take a guess.... by Ford+Prefect · · Score: 5, Funny

      Take a look at the username, and take a guess at mine :o)

      But shurely 1 /\ 1 = 1 ?

      --
      Tedious Bloggy Stuff - hooray?
    2. Re:Take a guess.... by Domini · · Score: 1

      Nevermind Shashdot Id: Check out my e-mail/domain.. ;)

    3. Re:Take a guess.... by RupW · · Score: 2, Interesting

      I don't get the whole mystery over 1+1=2 and huge proofs.

      Let's construct a number system from the very basics. We'll construct an infinite field over addition and multiplication. We have an additive unit which we'll call 0 and a multiplicative unit which we'll call 1. So we can add two multiplicative units to get 1+1. We call this 2. Therefore 1 + 1 = 2 *by definition of 2*.

      So what am I missing?

    4. Re:Take a guess.... by node+3 · · Score: 1

      The Internet: Proof that a million monkeys with keyboards won't produce the complete works of Shakespeare.

      The Complete Works of Shakespeare

      Yeah, I know. :-)

    5. Re:Take a guess.... by Gil-galad55 · · Score: 2, Informative
      Your system is axiomatic. If you assume that you have numbers that add and subtract as above, then of course they will! These are the axioms you have chosen for your system.

      If, on the other hand, you choose "simpler" axioms, then you might have to work very hard to get to the point of saying 1 + 1 = 2. Peano's axioms lead very quickly to this--in fact, they are about the same as the ones you stated. But you can assume any set of axioms you want. Much of mathematics is devoted to finding a "minimum set" of axioms for a particular branch, although as Godel showed, mathematics cannot be consistently axiomatic. Alas.

      --

      To follow knowledge like a sinking star, / Beyond the utmost bound of human thought. ("Ulysses", Tennyson)

    6. Re:Take a guess.... by bigdreamer · · Score: 4, Interesting

      "The difficulty of formal logic was demonstrated in the monumental Principia Mathematica (1925) of Whitehead and Russell's, in which hundreds of pages of symbols were required before the statement 1 + 1 = 2 could be deduced."

      http://mathworld.wolfram.com/Logic.html

    7. Re:Take a guess.... by pndmnm · · Score: 2, Insightful

      >although as Godel showed, mathematics cannot be consistently axiomatic. Alas. Mathematics *is* consistently axiomati[zable|c]. It's just not complete.

    8. Re:Take a guess.... by Anonymous Coward · · Score: 1, Informative

      To be precise, which is always a virtue in issues of math: It's at proposition 110.643 on page 83 of the second volume of Principia.

    9. Re:Take a guess.... by archeopterix · · Score: 2, Interesting
      I don't get the whole mystery over 1+1=2 and huge proofs.

      Let's construct a number system from the very basics. We'll construct an infinite field over addition and multiplication. We have an additive unit which we'll call 0 and a multiplicative unit which we'll call 1. So we can add two multiplicative units to get 1+1. We call this 2. Therefore 1 + 1 = 2 *by definition of 2*.

      So what am I missing?

      Usually "from the very basics" means "from zero and the successor operation".

      1+1=2 in the most popular formal systems translates to:

      S(0)+S(0)=S(S(0))

      where S(x) is the successor operation. To prove that, you have to use the addition axioms:

      x+1=S(x) // 1 is shortcut for S(0)

      S(a+b)=a+S(b)

      and of course the Peano axioms (look them up on google, I'm too lazy to retype).

      Try to prove 1+1=2 with this simple set of axioms. Note that you don't have x+y=y+x, x+(y+z)=(x+y)+z nor even x+0=x. The proof won't be several pages long, but still quite long.

    10. Re:Take a guess.... by Domini · · Score: 1

      It's on this page:

      http://e.co.za/e.html

      Please note that:

      "e(pi x sqrt(-1)) - 1 = 0"

      feels technically more elegant and complete than:

      "e^(pi x i) - 1 = 0"

      Because sqrt(-1) has two roots... -i and i. ;)

      Please point out if I'm wrong... would like to discuss this with someone with more knowledge.

    11. Re:Take a guess.... by PenguiN42 · · Score: 1

      S(0)+S(0)=S(S(0))

      where S(x) is the successor operation. To prove that, you have to use the addition axioms:

      x+1=S(x) // 1 is shortcut for S(0) ....

      The proof won't be several pages long, but still quite long.


      Rewrite x+1=S(x) as x+S(0)=S(x).
      Substitue x = S(0), S(0)=S(0)=S(S(0))

      What am I missing?

      --
      The following sentence is true. The preceding sentence was false.
    12. Re:Take a guess.... by jbolden · · Score: 1

      We'll construct an infinite field over addition and multiplication. We have an additive unit which we'll call 0 and a multiplicative unit which we'll call 1.

      OK I'll pick as my infinite field binary vectors of countable infinite length. We'll define the product of vectors component wise. So [1,1,1...] is the multiplicative unit (1). The sum of any vector with itself is the 0 vector so using your definitions 0 = 2.

      See wasn't so easy after all. You still screwed up even with casually tossing around notions like "field" and "unit" the existence of which are entirely non trivial.

    13. Re:Take a guess.... by pappin · · Score: 1

      Ahh but "1 & 1 = 1" also...

    14. Re:Take a guess.... by fatphil · · Score: 1

      "sqrt(-1) has two roots... -i and i."

      Nope.

      "sqrt(-1)" is not an equation, it is not a function of a variable, it has no roots.

      sqrt(-1) doesn't even have two values, as sqrt() is a function, having a single value. There are some, who are ignorant of the foundations of maths (namely what the set-theoretical definition of a function is), who try to pretend that a "multifunction", or "multi-valued function" is a kind of function, but it is not.

      x^2=-1 has two roots: +/-sqrt(-1)

      FP.

      --
      Also FatPhil on SoylentNews, id 863
    15. Re:Take a guess.... by nospmiS+remoH · · Score: 1

      I use a toddler and the "Sesame Street" Proof.

      1) Put an orange on a table and ask the toddler, "How many oranges are on the table?"

      2) Toddler replies, "One."

      3) Add one more orange to the table and ask the toddler, "How many oranges are on the table?"

      4) Toddler replies, "Two."

      5) Start explaining the concept of Occam's Razor to the toddler so he or she will simply roll his or her eyes when people start to argue about and explain basic things that are intuitively obvious to many three year olds.

      --
      !hoD
    16. Re:Take a guess.... by donnyspi · · Score: 1

      Pour one cup of juice into a tall, thin, 2 cup container. Pour one cup of juice into a short, fat, 2 cup container. Ask the toddler which one has more and s/he'll pick the tall thin one. S/he'll also be wrong. Proofs are needed because things aren't always as they seem.

    17. Re:Take a guess.... by Speare · · Score: 3, Funny
      But shurely 1 /\ 1 = 1 ?

      No, I'm serious. And stop spelling it 'shurely.'

      --
      [ .sig file not found ]
    18. Re:Take a guess.... by SimonShine · · Score: 1

      Another approach to proving that 1 = 1 (or 1 + 1 = 2 if you want to go that far!) is by using surreal numbers. There's a good guide to them at http://www.tondering.dk/claus/surreal.html. I think it is considered recreational mathematics. :)

      --
      Take off every 'ZIG' !!
    19. Re:Take a guess.... by nospmiS+remoH · · Score: 1

      True, but this is also introducing more complex concepts such as volume and area. I talking first order, discrete, basic stuff here. Anyone of normal mental capacity that has had the opportunity of leaning their 1,2,3's will be able to count the oranges the same way.

      --
      !hoD
    20. Re:Take a guess.... by fatphil · · Score: 1

      That's a field of finite characteristic though.

      Hmmm, actaully you knew that, I'm sure. It was probably grandparent who didn't.

      FP.

      --
      Also FatPhil on SoylentNews, id 863
    21. Re:Take a guess.... by funkstaridf · · Score: 1

      If you want to include more than one solution: e^(i x pi x (1 + 2Z)) + 1 = 0 where (1 + 2Z) is shorthand for the odd integers. So your equation is simply shorthand for two of the above, and not really anymore satysfying. In fact, I much prefer e^(i x pi) + 1 = 0 because there's no amiguity, and the symbols are all used exactly one time. Also remember that e^(i x pi) is -1, so it's plus, not minus.

    22. Re:Take a guess.... by archeopterix · · Score: 1
      Rewrite x+1=S(x) as x+S(0)=S(x).
      Substitue x = S(0), S(0)=S(0)=S(S(0))

      What am I missing?

      The proof is OK - sorry, I thought that 1+1=2 doesn't have such a short proof. Try 1+0=0 - this should be a bit harder :-)
    23. Re:Take a guess.... by Fgarb · · Score: 1

      The hard part comes in defining *all* the things. You need to define addition, equality, and you assume (or define) discrete units. For non-maths examples, if I am singing a song, and someone has a harmonizing melody, and we sing at the same time ("adding") them, we do not have two discrete songs, but only one song. Similarily, if I add one leg, one arm, one torso, etc, I will not get a person, no matter how many body parts I stitch together. (Dr. V. Frankenstein's work notwithstanding) What makes "1+1=2" important, to me, is that as long as I define what I mean by "1", "+", "=", and "2", then "1+1=2" will always be true. I won't get 1+1=3 tomorrow, or get 1+1=0 because I'm in the US and not Turkey.

    24. Re:Take a guess.... by PenguiN42 · · Score: 3, Funny

      Try 1+0=0 - this should be a bit harder :-)

      You're right, that would be a hard proof ;)

      --
      The following sentence is true. The preceding sentence was false.
    25. Re:Take a guess.... by Gil-galad55 · · Score: 1

      Right right. I should have been more clear on that. Thanks for the correction! :)

      --

      To follow knowledge like a sinking star, / Beyond the utmost bound of human thought. ("Ulysses", Tennyson)

    26. Re:Take a guess.... by Domini · · Score: 1

      True, true... theta could be odd multiples of pi radians... why not just use +i then...

      After speaking to a friend of mine I've convinced myself of the simle beauty of the equation again.

      PS: Yup, sorry 'bout the -1.

    27. Re:Take a guess.... by jbolden · · Score: 1

      Well sure. Once he has infinite characteristic there is a natural embedding of the integers into his field and thus "1+1=2" (as he defined it) means pretty much the same thing in all infinite characteristic fields.

    28. Re:Take a guess.... by Anonymous Coward · · Score: 0

      Nonsense...;-)

      1 + 1 = 3

      (one (male) plus one (female) = 2 adults and 1 baby...:-P

    29. Re:Take a guess.... by Fortran+IV · · Score: 1

      Give a toddler who is just learning to count a piece of chalk. Give yourself a piece of chalk. Ask if you and the toddler have the same amount of chalk. The toddler will say, "Yes."

      Break your piece of chalk in two. Now ask if you and the toddler have the same amount of chalk. The toddler may go either way.
      --
      I figure by 2030 or so my 6-digit UID will be something to brag about.
    30. Re:Take a guess.... by Ohreally_factor · · Score: 1

      That's why it's called Gödel's Incompleteness Theorem. =)

      When I was a freshman in college, they had us read Gödel, Escher, Bach by Douglass Hofstadter for a core humanities class.

      --
      It's not offtopic, dumbass. It's orthogonal.
  6. sing it...!! by Anonymous Coward · · Score: 0

    Nothing from nothing leaves nothing!

    1. Re:sing it...!! by hackwrench · · Score: 1

      I'm not sure where that's from...

      Here try this:

      Nothing comes from nothing, nothing ever could...

    2. Re:sing it...!! by Anonymous Coward · · Score: 0

      buuuuuuut somewhere in my youth or childhooooood....

      OK. How about this:

      Let X=X..... Laurie Anderson?? ring a bell?

      There have got to be a lot of equations in songs, right?

    3. Re:sing it...!! by Anonymous Coward · · Score: 0

      Check this out....

      I will derive!!
      http://www.amiright.com/parody/70s/glori agaynor24. shtml

  7. Geometry and Algebra by metlin · · Score: 4, Interesting

    In my opinion, the most important equations are those that brought together Algebric representation of Geometry -- that has been the single most fundamental basis for today's advancement in mathematics and physics.

    1. Re:Geometry and Algebra by quetzalc0atl · · Score: 2, Insightful

      of these, i would say that perhaps the most important is the Generalized Stokes Theorem: http://mathworld.wolfram.com/StokesTheorem.html

      this says that the integral of a form over the boundary of a manifold is equal to the integral of the exterior derivative of the form over the manifold itself. it shows that the derivative itself implies topological content!

      this beautiful equation says everything one needs to know about the calculus of geometry. from this equation one can derive the fundamental theorem of calculus, vector analysis, antisymmetric tensors, metrics, etc.

      i may get this thing tatooed on myself.

    2. Re:Geometry and Algebra by metlin · · Score: 1

      I simply couldn't agree with you more!

      GST is probably one of the most brilliant mathematical constructs of all time.

      What more, it even works on Hilbert Space matrix tensor operations, something that most general theorems on manifolds cannot always boast of.

    3. Re:Geometry and Algebra by quetzalc0atl · · Score: 1

      i did not know this. then again, i am utterly ignorant of quantum maths..but chalk another one up for the GST!

      to this day i do not understand why vector analysis is not being taught in terms of differential forms. i think maybe its because ppl associate diff. forms with the more traditional tensors and say "whoah, too many indices dude".

    4. Re:Geometry and Algebra by metlin · · Score: 1

      Vectory analysis is taught in differential forms, but in other ways.

      The problem is that if you take a vector and differentiate it, you break it down into its components and non-trivial vector differential variables essentially bringing it into a simple differential form, which can be expressed in terms of other existing methods.

      Differential forms are indeed used as basis for vector analysis, classical electrodynamics is an example of this. The reason Tensors work is not because of anything else but simply because they can express really large indices and really large matrices/vector combinations in very simple forms. That, and the fact that they have a great degree of generalizability (in a mathematical and physical sense, if you know what I mean) helps the use of tensors. Another thing is that tensors have certain advantage of scaling up quite easily and being manipulate-able (wonder if such a word exists) across several indices in terms of variables/dimensions/factors/anything. I mean, look at Hilbert Space - so many dimensions out there, it's kinda huge :-)

      Oh well. So much for math, let me go fix myself a drink.

    5. Re:Geometry and Algebra by metlin · · Score: 1

      And oh, forgive me if that sounded weird - low on sleep, high on caffeine, very high on work.

      BZZZZT!

    6. Re:Geometry and Algebra by quetzalc0atl · · Score: 1

      no, it makes perfect sense what you are saying.

      i guess when i think of vector analysis, i think of having to memorize formulas for divergence, curl, formula for curve integrals, etc. no need to memorize when u know the GST!

      i am still learning the subject somewhat, i have a good background on tensors and forms but my knowledge of topology is next to nothing.

  8. Well... by Anonymous Coward · · Score: 5, Funny
    I'm quite fond of this one...

    B*u*pi * integral of e^x

    Hint: Try writing it in mathematical notation.

    1. Re:Well... by Anonymous Coward · · Score: 5, Informative

      thats buttsex for those of you who dont know how to write an integral

    2. Re:Well... by metlin · · Score: 5, Funny

      Slashdot - the only place where you could stay ontopic and mention buttsex and integral in the same sentence _and_ get modded informative.

      Yay!

    3. Re:Well... by stud9920 · · Score: 0

      don't you have to integrate wrt some differential ?

    4. Re:Well... by zumbojo · · Score: 1

      A high school favorite:

      integral of e^x = function(U^n)

      or if calc was a long time ago for you: integral of e^x = function(U^n)

    5. Re:Well... by Anonymous Coward · · Score: 0

      It needs a differential on the end for it to be meaningful.

    6. Re:Well... by Morphine007 · · Score: 1

      yes... but it's kind of a short form; e is a constant and x can be assumed to be a variable, unless you're a fan of writing math that doesn't follow convention (just to try and confuse people) so you can assume that you're integrating over x... the dx is implied. Go to citeseer and find a math paper... any math paper... odds are you'll see a whole whack of "shorthand" like this. The most common seems to be sigmas with no range.

    7. Re:Well... by NiTr|c · · Score: 1

      Along the same lines is...

      integral of e^x = e^x+c

      I always remembered this equation in school as "sex = extasy". Write it out and you can see why.

      --
      Try actually thinking for yourself. It's quite refreshing.
    8. Re:Well... by c4ffeine · · Score: 1

      Personally, I prefer the following. Write it in correct notation and you'll see.

      The integral of e^x equals f of (u subscript n).

      My calc teacher showed us that one...

      --
      "73% of quotes on the Internet are made up" -Ben Franklin
    9. Re:Well... by Anonymous Coward · · Score: 0

      could be worse...could be
      f of u is less than k times m subscript e

    10. Re:Well... by Anonymous Coward · · Score: 0

      I've always postulated that if f(n) = e^x then f'(n) is the same as the integral of e^x

      so f'n = integral of e^x

      But what do I know, it's been ages since I've done any of that fancy shmancy math.

    11. Re:Well... by Anonymous Coward · · Score: 0

      Slashdot - the only place where you could stay ontopic and say that a post about buttsex and integral was moderated informative, _and_ get modded funny.

      Yay!

  9. ok not the greatest by themusicgod1 · · Score: 1

    but my personal favorite :)

    --
    GENERATION 26: The first time you see this, copy it into your sig on any forum and add 1 to the generation.
  10. Euler's equation by etnoy · · Score: 0

    e^in + 1 = 0

    I read about this two weeks ago in a local newspaper. Didn't the article mean e^(i*\pi)+1=0 ?
    Anyway, it could be my fonts confusing me.

    --
    Quantum hacker.
    1. Re:Euler's equation by faragon · · Score: 1

      As historic curiosity, Euler said that the idea was given directly by God. Previous posts were right: mobile phones couldn't work without it as far as filters and modulation is required. The Euler formula is used extensively on signal processing (neighbor to Fourier's frequency analysis).

      Another quite cool formula could be: s = e^(jw)
      (tribute to Laplace et al)

  11. H = F ^ 3 by Rob_Warwick · · Score: 3, Insightful

    Happiness = Food x Friends x Fun
    From Woz.

    It's the most important and beautiful equation I've ever seen.

    1. Re:H = F ^ 3 by cwebb1977 · · Score: 0

      Happiness = Beer x (Women + Beauty(Women))

      --
      www.weberseite.at
    2. Re:H = F ^ 3 by segmond · · Score: 1

      basically, it's possible to have any at 1, and the rest huge.

      ie friends and fun = 1, food = 1000
      is equal to friends = 10, fun = 10, food = 10

      i think not!

      --
      ------ Curiosity killed the cat. {satisfaction brought it back | it didn't die ignorant | lack of it is killing mankind
    3. Re:H = F ^ 3 by superstick58 · · Score: 1
      It's a good equation but not quite complete. Try this:

      H = F^3 + B

      Hapiness = Food x Friends x Fun + Beer

    4. Re:H = F ^ 3 by Rob_Warwick · · Score: 1

      Ok, I don't drink but from what I know, the equation should be this:

      H = F^2 x (F+B)

  12. How about... by Paster+Of+Muppets · · Score: 2
    x = x0 + V * cos (theta)* t, y = y0 + V * sin (theta) * t - (1/2) * g * t^2.

    Projectile equations of motion, very useful in FPS games.

    --
    Due to lack of disk space this user has been discontinued
  13. Clearly the best by obi-1-kenobi · · Score: 1

    C^2=A^2+B^2 or or Volume = 4/3 * pi r^3

    --
    "You win again Gravity!" -Futurama (Zapp)
  14. that's an easy one.. the answer is by peculiarmethod · · Score: 3, Funny

    First we state that women require time and money:
    Women = Time X Money

    And as we all know "time is money"

    Time = Money

    Therefore by substituting Money for Time we get:

    Women = Money X Money

    Women = (Money)2

    And because "money is the root of all evil" we therefore can state:

    Money = (Evil)1/2

    And Since

    (Money)2 = Women

    Then (Money)2 = Evil

    And we are forced to conclude by substituting "women" for "(money)2" from above that:

    Women = Evil

    --
    ** "It's not my job to stand between the people talking to me, and the ones listening to me." -- Pego the Jerk
    1. Re:that's an easy one.. the answer is by faragon · · Score: 1

      Absolutelly brilliant. Yours is the funniest commentary, still wrong, I've seen in weeks :-)
      Anyway, my woman takes a 30% of my spare time, then I spend the 60% left to my Idle process.

    2. Re:that's an easy one.. the answer is by commodoresloat · · Score: 1, Funny

      I'll settle for my favorite syllogism:

      All men are mortal
      Socrates is a man
      Therefore, all men are Socrates.

    3. Re:that's an easy one.. the answer is by Seahawk · · Score: 1

      You mean this?

    4. Re:that's an easy one.. the answer is by Anonymous Coward · · Score: 0

      what do you do with the other 10% ?

  15. ThinkGeek t-shirt by bokmann · · Score: 5, Funny

    My favorite is the thinkgeek tshirt that says "2+2=5 for extremely large values of 2".

    It is not just funny... if you consider the numbers not as integers, but as any float value with that integer as the first number, it is true.

    1. Re:ThinkGeek t-shirt by dabigpaybackski · · Score: 1
      My favorite is the thinkgeek tshirt that says "2+2=5 for extremely large values of 2".

      I believe that one is referred to in literary circles as "Orwell's Postulate."

      --
      "OH SHIT, THERE'S A HORSE IN THE HOSPITAL!"
    2. Re:ThinkGeek t-shirt by GauteL · · Score: 1

      It is only true if the precision of your 2's is really bad. :-)

      You have to have a combined relative error of:

      \epsilon_{rel} = (5-4)/4 = 0.25

      This is very, very rarely an acceptable error.

    3. Re:ThinkGeek t-shirt by zoefff · · Score: 1

      would 2.5 not be sufficient? I assume that 'extremely large' would be something like 2.999999...etc

    4. Re:ThinkGeek t-shirt by crull · · Score: 0

      No it wouldnt. I'm sorry!

      --
      this is not my signature.
    5. Re:ThinkGeek t-shirt by rokzy · · Score: 1

      depends. in measurements your error is usualy not defined by float precision. there are many things we still can't measure accurately. admitting that and giving justifiable error bars makes you a better scientist than trying to claim better accuracy and getting smacked down by peer review. an example is the value of the magnetic field in a coronal loop measured to be 13 +/- 9 G.

    6. Re:ThinkGeek t-shirt by Mats+Kristoffersen · · Score: 1

      On a related note, my favorite proverb would probably be "It need not be true as long as it's well said."

    7. Re:ThinkGeek t-shirt by tootlemonde · · Score: 2, Informative

      "2+2=5 for extremely large values of 2" is sometimes called "Fermat's next-to-last theorem" and is said to be the occasion for a duel with sabers between Tycho Brahe and Manderup Parsbjerg in 1566.

      You can read about the grisly outcome here as part of the discussion "Did Tycho Brahe really have a silver nose?".

    8. Re:ThinkGeek t-shirt by Zilla40104 · · Score: 1

      I'd think 2+2=6-epsilon for very large values of 2, and that the probalility that, at that error rate the value actually would be 6 is quite high ... is this Turing explainable?

    9. Re:ThinkGeek t-shirt by Anonymous Coward · · Score: 0
      "It need not be true as long as it's well said."
      See also, in Italian (ancient language): "Se non è vero, è ben trovato." ("If it's not true, it's a good story.") Possibly by Giordano Bruno (burned at the stake by the Inquisition Feb. 17, 1600 on the Campo dei Fiori in Rome).
    10. Re:ThinkGeek t-shirt by asadsalm · · Score: 1


      In actuality, 2 + 2 = 6 for extremely large values of 2.

    11. Re:ThinkGeek t-shirt by AnuradhaRatnaweera · · Score: 1
      In actuality, 2 + 2 = 6 for extremely large values of 2.

      Not if rounding, rather than floor, is in action. 2.5 + eps will be an `extremely small' value of 3! :-)

      Alice said, as gravely as she could, `They might go different ways.' But she couldn't help thinking to herself `What dreadful nonsense we are talking!'
    12. Re:ThinkGeek t-shirt by Anonymous Coward · · Score: 0

      Nope, because that's not true until "large_2 >= 2.75", once you reach 2.5 it's no longer a "large value of 2". It's now a "small value of 3", and "3+3=6 for small values of 3" doesn't exactly have the same humor, does it?

    13. Re:ThinkGeek t-shirt by mrtroy · · Score: 1

      Actually for floating point, the maximum 2+2 could be is 5 for extremely large values of 4.

      --
      [I can picture a world without war, without hate. I can picture us attacking that world, because they'd never expect it]
    14. Re:ThinkGeek t-shirt by tootlemonde · · Score: 1
      The general form of the equation is:
      2 + 2 > 4 for sufficiently large values of 2 or sufficiently small values of 4

      or, put another way:

      a + a = 2a + b for sufficiently large values of a or small values of b

      or, skipping some steps:

      a = a + b for sufficiently large values of a or small values of b.

      Note the similarity of a = a + b to the Mandelbrot iterative equation Z = Z^2 + C, suggesting that if the precision of a is bad or that every a is an approximation of a + b, then a straight line is a special case of the Mandelbrot set (a fractal) or, more generally, all smooth curves are an approximation of a fractal.

    15. Re:ThinkGeek t-shirt by igny · · Score: 1

      That reminded me about a story about some engineers who constructed a conjecture, where they considered an equation which was true for all integer n, and then they just let n go to 0. It took a decade for mathematicians to prove this conjecture rigorously.

      --
      In theory there is no difference between theory and practice. In practice there is. - Yogi Berra
    16. Re:ThinkGeek t-shirt by Cryogenes · · Score: 1

      The equation 2+2=5 goes back to an african tribe that uses knots tied in a rope for counting.

      If you combine a two knot rope with another two knot rope you get a five knot rope.

    17. Re:ThinkGeek t-shirt by Anonymous Coward · · Score: 0

      you may want to look at this

    18. Re:ThinkGeek t-shirt by rsadelle · · Score: 1

      That's only part of why I prefer this equation: 1+1=3, for large values of 1.

  16. I'd have to go for the classic: by Biotech9 · · Score: 0
  17. Dirac's equation of 1/2 spin: by Jesrad · · Score: 4, Interesting

    ih/2Pi dPhi/dt = hc/2iPi (A1 dPhi/dx1 + A2 dPhi/dx2 + A3 dPhi/dx3) + A4 mc(squared)Phi

    Said by Hotson to be the Equation of Everything. First part, second part. Worth a read IMO.

    --
    Maybe we deserve this world ?
    1. Re:Dirac's equation of 1/2 spin: by Abcd1234 · · Score: 1

      Pfft... the guy isn't even a physicist. Meanwhile, he goes on to write about how the entire physics establishment fscked up, and how he is, apparently, the only one smart enough to realize the Real Truth. If this doesn't fit the definition of crackpot "science", I don't know what does...

    2. Re:Dirac's equation of 1/2 spin: by Jesrad · · Score: 1

      Oh yes, you're right. We should burn him at the stake.

      To tell the truth I'm not satisfied with his failure to explain the total 1/2 spin of the nucleons, his explanation on how he comes up with the correct number of positron-electron pairs to build a neutron (and lighter baryons), and the lack of a calculation of the gravitational constant from the g-factor of the electron following his magnetogravitics explanation. Other than that he opens surprising and interesting ways to investigate. It'd be interesting to see what experiments he comes up with to validate the theory.

      --
      Maybe we deserve this world ?
    3. Re:Dirac's equation of 1/2 spin: by Abcd1234 · · Score: 1

      Oh yes, you're right. We should burn him at the stake.

      I never said that. However, his work does *not*, in any way, qualify for a spot on the list of Greatest Equations Ever. The fact is, this person is 1) convinced science is wrong, 2) convinced he knows the answer, and 3) isn't *qualified* to decide either of these things. So, until his work is either 1) peer reviewed and validated or 2) verified experimentally, and these experiments are repeated by other, reputable scientists, his work will continue to lack credibility, and so will be ignored.

      It'd be interesting to see what experiments he comes up with to validate the theory.

      Agreed, and I'd love for him to come up with such experiments, and for others to validate his work. But I ain't holdin' my breath, any more than I'm expecting a breakthrough in cold fusion or gravity shielding.

    4. Re:Dirac's equation of 1/2 spin: by Anonymous Coward · · Score: 0

      Please save electrons

      Delambertian^2 Psi = M^2 Psi
      hbar = c = 1

      Thank you

    5. Re:Dirac's equation of 1/2 spin: by Jesrad · · Score: 1

      So, until his work is either 1) peer reviewed and validated or 2) verified experimentally, and these experiments are repeated by other, reputable scientists, his work will continue to lack credibility, and so will be ignored.
      How will this work be reviewed or tested if it is ignored ? It looks like a catch-22.

      Oh, and FYI cold fusion has done some remarkable progress those last 15 years ;)

      --
      Maybe we deserve this world ?
    6. Re:Dirac's equation of 1/2 spin: by Abcd1234 · · Score: 1

      How will this work be reviewed

      He could submit it to one or more legitimate scientific journals. Or he could present the work to a qualified physicist and try to get them on board. Or he could actually, you know, work toward a physics degree, in which case he could use this work his PhD dissertation.

      or tested

      You said it yourself, he could attempt to develop experiments to test his theories. And as long as these experiments can be repeated, there should be no problems.

      Oh, and FYI cold fusion has done some remarkable progress those last 15 years

      If, by progress, you mean it's been largely debunked, I couldn't agree more! ;)

    7. Re:Dirac's equation of 1/2 spin: by Jesrad · · Score: 1

      He could submit it to one or more legitimate scientific journals. Or he could present the work to a qualified physicist and try to get them on board.

      Right, he'll present it to people who are pathological disbelievers like yourself and it will be ignored instead of being reviewed. Catch-22, as I said.

      --
      Maybe we deserve this world ?
    8. Re:Dirac's equation of 1/2 spin: by naasking · · Score: 1

      However, his work does *not*, in any way, qualify for a spot on the list of Greatest Equations Ever.

      It's not his equation. It's the Dirac's equation, arguably among the most important discoveries of 20th century physics.

      1) convinced science is wrong

      That's not too hard to believe. In fact, I'm *sure* science is wrong, and you should be too. Until we have a complete and consistent explanation for all phenomena, any model we use is incomplete at best.

      2) convinced he knows the answer

      Most people are convinced they are right, until proven otherwise.

      3) isn't *qualified* to decide either of these things

      The only qualifications necessary for a science are a logical argument supported by facts. A university can't give you that; it's a product of an inquiring mind.

      So, until his work is either 1) peer reviewed and validated or 2) verified experimentally, and these experiments are repeated by other, reputable scientists, his work will continue to lack credibility, and so will be ignored.

      None of which mean he's wrong.

    9. Re:Dirac's equation of 1/2 spin: by Abcd1234 · · Score: 1

      Umm, by the very definition of that presentation, I am not, by any means, a "pathological disbeliever". If this individual was, say, qualified in the field, I might pay a little more attention to his claims. If he was able to successfully test his theories with experiments, I would most certainly be willing to hear him out. However, until he's either 1) achieved a doctorate in Physics, thus proving that he's competant enough to question fundamental building blocks of theoretical physics, or 2) proved his theories with valid, repeatable experiments, I will continue to be highly skeptical, as you should you.

      Frankly, it sounds to me like you should try to be a little *more* skeptical. After all, you're putting an awful lot of stock into the claims of someone who can't even earn a degree in the area (or even a related area... AFAICT, he doesn't have a degree of *any kind*!) he's claiming to study.

      Oh, and BTW, you might want to look at some of Hotson's other claims. He's done a talk on Dirac's Equation And A Possible Physical Basis For Some of Astrology (astrology!), and apparently he has some interesting beliefs regarding ball lightening, "time storms", and other phenomena. So, why was it that I should bother paying any attention to this guy? He's looking more and more like a total crackpot the more I dig...

    10. Re:Dirac's equation of 1/2 spin: by Abcd1234 · · Score: 1

      t's not his equation. It's the Dirac's equation, arguably among the most important discoveries of 20th century physics.

      The poster presented the equation with tbe belief that it be included on the list because it is "Said by Hotson to be the Equation of Everything.", or so I interpreted his post. In this I could have been wrong.

      That's not too hard to believe. In fact, I'm *sure* science is wrong, and you should be too. Until we have a complete and consistent explanation for all phenomena, any model we use is incomplete at best.

      And I'm pretty sure you're very adept at splitting hairs. Hotson isn't just claiming minor holes in existing theory. He has the belief that the entire scientific establishment got a major portion of fundamental physics completely wrong, despite massive experimental evidence which largely validates these theories, while at the same time being totally unqualified (based on a lack of a formal education in the area) to make this sort of judgement.

      This would be akin to me saying "Hey, those guys researching cancer got it totally wrong! See, I was in a first year biology class and I asked <insert question here>, and I didn't believe their answer, even though I don't have the knowledge to make that sort of judgement, and so I came up with this theory that totally invalidates 50 years of work in the area! Now, sure, the only thing I know about medicine is a few undergrad courses in bio and a really cool show I saw on the Discovery Channel, but I figure that's enough to propose a theory that goes against everything dicovered by many more knowledgeable people than me. Oh, and BTW, my theory also provides evidence for telepathy, alien abductions, and Bigfoot."

      Most people are convinced they are right, until proven otherwise.

      Yeah, for example I'm convinced you don't know how to make a useful argument. There's one problem, though: I'm not qualified to make that judgement. Why? Because I don't know you or your posting history. Therefore, what I have to say regarding your ability to debate is largely immaterial and should be ignored by any logical individual unless additional supporting evidence is provided.

      The only qualifications necessary for a science are a logical argument supported by facts.

      Agreed. But if you don't have the necessary education, and hence understanding, to put forward a valid, logical argument, then that significantly reduces the weight of any such argument that is put forth. And, guess what, a university degree is pretty decent evidence that someone has acquired the necessary knowledge.

      None of which mean he's wrong.

      Nope, it just makes it highly likely.

  18. 0 = 0 by RAMMS+EIN · · Score: 5, Funny

    My favorite is 0 = 0, because it's the one that most often indicates you're done with the math exercise. :-)

    --
    Please correct me if I got my facts wrong.
    1. Re:0 = 0 by Temporal+Outcast · · Score: 1

      Are you kidding me?

      Ramanujan's Tau function had so much trouble proving that equality, and generalizing it for polynomial continued fractions.

      Not to mention the difficulty people have had in proving that trivial equalities are indeed generalizable across various degrees.

      Dude, that equation probably has had more effort put in (and continues to have more effort put in, in terms of trivial results in infinity-related operations and operands) than any other.

      My favorite is 0 = 0, because it's the one that most often indicates you're done with the math exercise. :-)

      And it also indicates the beginning of a lot of problems for a mathematician.

      --

      Vote for a Man, Vote for Bush!
      Not a liberatarian flipflop hippie.
    2. Re:0 = 0 by _xeno_ · · Score: 3, Funny

      Conversely, my "favorite" is 1 = 0, because it means that you get to spend another 5 minutes figuring out what you did wrong.

      --
      You are in a maze of twisty little relative jumps, all alike.
    3. Re:0 = 0 by zx75 · · Score: 1

      See, whenever I get 1=0 in a math proof, my answer is always :
      "Therefore contra. QED"

      Regardless of whether I specified my proof as such in the beginning or not ;).

      --
      This is not a sig.
    4. Re:0 = 0 by mikecarrmikecarr · · Score: 1

      I remember using this in an upper-year math class at university. We were all staring at the whiteboard, trying to figure out how the complicated left-hand-side equalled the right-hand-side. Nothing was going anywhere, so I thought I'd head to one of the Tim Horton's on-campus (gotta love Canadian universities). Before I went out the door I jokingly multiplied both sides of the equation by 0, wrote "0=0 therefore, true" and went for coffee. How was I supposed to know that some people actually submitted that as an answer to the teacher? Man, did I catch hell for that. Anyways, always remember, if you're lost in math, multiply everything by 0 and your problems will turn out to be nothing ;-)

      --

      ID-10-T is a way of life

  19. Gauss by dasnake · · Score: 1

    I() means integral in the proper space I(div(F)dV) = I(Fda) That's damn useful.

  20. F=ma by Colin+Smith · · Score: 1, Funny

    Gotta love motorcycles. Mmmwwhahahaaaa.

    --
    Deleted
  21. 1+1 = 3 by pyrros · · Score: 0

    1 + 1 = 3
    For large values of 1 (and small values of 3)

  22. dupe of old poll by Gathers · · Score: 5, Informative

    "What is your favorite equation? ..."
    Shashdot has already covered this in a poll! We all already know that E=mc^2 is the overall favorite, closely followed by F=ma.
    http://slashdot.org/pollBooth.pl?qid=804

    1. Re:dupe of old poll by Spock+the+Baptist · · Score: 1

      I'm constantly having to remind my University Physics I & II students that Newton's Second Law is NOT F=ma,
      but rather F=dp/dt
      where F, a, and p are vectors.
      Recall: p=mv (v is also a vector).
      Therefore, according to the multiplication rule from calculus,
      dp/dt= m*dv/dt + v*dm/dt.
      Now if m is constant with time then dm/dt=0, and F=ma holds as the second term disappears.

      --
      "Oh drat these computers, they're so naughty and so complex, I could pinch them." --Marvin the Martian
    2. Re:dupe of old poll by FuzzyBad-Mofo · · Score: 1

      Personally, I'm partial to the quadratic equation:

      (-b ± (b^2-4ac)^(1/2))/2a = 0

      (of course taking a number to a 1/2 power is just another way of saying "square root")

    3. Re:dupe of old poll by the+quick+brown+fox · · Score: 1

      Actually I believe "Favorite Equation..." is in the lead. See?

  23. Sometimes greatness is in the eye of the beholder by Anonymous Coward · · Score: 0

    To paraphrase one of my math professors:

    "These sums may look incredibly ugly to you. But I got my tenure by working on them, so they're beautiful to me."

  24. my favourite physics equation by JaF893 · · Score: 1

    C^2 = 1 /(0*0)

  25. Einstein's FULL equation by physicsphairy · · Score: 3, Informative
    The equation everyone knows offhand is E=mc^2 (even if they don't know what it means), but few people know that the full equations is E=m^2c^4 + p^2c^2. 'p' is momentum, so when you're talking about just the rest mass of the particle you have E=mc^2.

    Anyway, just thought I'd share that because E=m^2c^4 + p^2c^2 is my favorite equation and most people think it looks a little familiar but wouldn't know what it was without a little additional explanation.

    1. Re:Einstein's FULL equation by dasnake · · Score: 5, Informative

      I think your favorite equation should be E^2=m^2c^4+p^2c^2.
      Nah?

    2. Re:Einstein's FULL equation by Paster+Of+Muppets · · Score: 2, Insightful

      It's actually E^2 = (m^2 * c^4) + (p^2 * c^2), so for objects with no momentum (only rest mass energy) you can sqaure-root both sides and get E = m * c^2

      --
      Due to lack of disk space this user has been discontinued
    3. Re:Einstein's FULL equation by physman · · Score: 2, Insightful

      Another way of writing the equation E=mc^2 is to we write what m is. m = m0 / [1 - v^2/c^2] (Where m0 is the rest mass - i.e. the mass of the particle when it is stationary - relativity states that the mass of a particle changes when its velocity increases - f=ma is only a newtonian approximation). Therefore, E = m0 c^2 / [1 - v^2/c^2}

      --
      Murphy's Law of Research: Enough research will tend to support your theory.
    4. Re:Einstein's FULL equation by Anonymous Coward · · Score: 0

      Bah. G = 8 pi T

      There's the large scale structure of the universe right there.

    5. Re:Einstein's FULL equation by ggeens · · Score: 4, Informative

      It's actually E^2 = (m^2 * c^4) + (p^2 * c^2)

      More like: E^2 = (m0^2 * c^4) + (p^2 * c^2)

      m0 is defined as the mass at rest (v = 0). If you substitute m = m0 / sqrt(1 - v^2/c^2), you can rework that to E = mc^2. And, if v = 0, you get E0 = m0c^2, the "energy at rest" of an object.

      I agree with the original poster, the full version is much more useful than the E = mc^2 form. The short form hides one of the most important conclusions of relativity theory: that mass is a function of speed.

      --
      WWTTD?
    6. Re:Einstein's FULL equation by Eliezer+Yudkowsky · · Score: 1

      I believe you mean E^2=m^2c^4 + p^2c^2.

      --
      Planetary death rate: 150,000 lives per day. End the slaughter
    7. Re:Einstein's FULL equation by Anonymous Coward · · Score: 0

      Duh, E^2=m^2c^4+p^2c^2

      Set p=0 (stationary object) and you get E=mc^2

    8. Re:Einstein's FULL equation by Anonymous Coward · · Score: 0

      Huh? Why does this (#10619091) post have a score of 1? It is the only post of this whole thread that seems to be written by someone who knows what he's talking about. Of course Einstein meant the real mass, not the rest mass, with m, so E=mc^2 is correct. Moderate to 5, Insightful please.

    9. Re:Einstein's FULL equation by physicsphairy · · Score: 2, Informative
      *sheepish grin* That's the second time I've done that now.

      I sure hope my calculations aren't where all that inexplicable "dark matter energy" has been coming from. . .

    10. Re:Einstein's FULL equation by Zilla40104 · · Score: 0

      Exactly my piont, but don't forget Kepler, Lorentz and others that actually made it possible! I personally like Fourier's transformation.

    11. Re:Einstein's FULL equation by joshv · · Score: 1

      Actually that's E^2=m^2c^4 + p^2c^2.

    12. Re:Einstein's FULL equation by Dr.+Evil · · Score: 1

      F=ma is the definition of F. The fact that mass is variable does not make it an approximation.

    13. Re:Einstein's FULL equation by Anonymous Coward · · Score: 0

      ahh, Einstein's field equations of General Relativity. Also my vavourite equation. You should mention that
      G = the so called Einstein tensor (describes the shape of curved space-time)
      T = relativistic stress-energy tensor (a kind of matrix that contains mass density, energy density and momentum)

      So, on the right hand side of Einstein's Field Equation we have the sources of gravitation (mass and energy) while on the left hand side we have the shape of space time. What this equation basically sais is how the shape (curvature etc.) of space time is given by the distribution of mass and energy.
      Unfortunately, components of G also appear in T, therefore this equation is not easy to solve.

    14. Re:Einstein's FULL equation by Tim+C · · Score: 1

      The short form hides one of the most important conclusions of relativity theory: that mass is a function of speed.

      Only to those who weren't paying attention in special relativity lectures...

    15. Re:Einstein's FULL equation by pjt33 · · Score: 1

      Douglas Adams already explained dark matter. It's the polystyrene packing that telescopes are protected with in transport...

    16. Re:Einstein's FULL equation by Anonymous Coward · · Score: 0

      the full version is much more useful than the E = mc^2 form

      That's true and that's because strictly speaking mass and energy are the same *by definition*. For historical reasons (and limited human abilities) we use two names for it - energy and mass, but using different notation we could get rid of one quantity and use only one name. Einstein's contribution was that he discovered we use two different words for the same thing.

    17. Re:Einstein's FULL equation by WhatsAProGingrass · · Score: 1

      Well, I'm pretty sure part of the equation is missing. It has to do with relativity and when things are moving, the mass changes.

      --
      Mark
    18. Re:Einstein's FULL equation by balaam's+ass · · Score: 2, Insightful

      It looks like you're considering some kind of low-velocity expansion of an equation for the full energy of a particle, which has a (1/sqrt(1-v^2/c^2) in it. So, you're not even giving the "full" equation.

      For my part, I was actually amazed that (what is typically called) "the Einstein equation", (TeX notation)

      G_{\mu\nu} = 8\pi T_{\mu\nu}

      didn't even appear in the article. I mean, if we're talking "greatest equations ever", something that describes the curvature of spacetime AND the motion of objects in it, which uses 10 nonlinear coupled partial differential equations to do it, but can be derived from a variational principle --- hell, yea it's messy, but it's also pretty simple, powerful and maybe even elegant. The fact that it's still keeping researchers busy to even SOLVE the thing 100 years later certainly makes it interesting.

      (How come this didn't make the list, but "e^{i\pi}+1 = 0" did? Big deal.)

    19. Re:Einstein's FULL equation by Anonymous Coward · · Score: 0

      It is possible to write the equations in terms of a change in mass, but most will tell you that it's better to think of the mass as staying the same, and the momentum and energy which change with relative velocity.

    20. Re:Einstein's FULL equation by Anonymous Coward · · Score: 1, Informative

      I agree with the original poster, the full version is much more useful than the E = mc^2 form. The short form hides one of the most important conclusions of relativity theory: that mass is a function of speed.

      Actually that's not actually what's in there. There's no such a thing as 'mass at rest'... At rest with respect to whose frame of reference???

      A more proper terminology and interpretation is that there's a thing we call mass which is the proper mass of an object, or the mass we measure on the frame of reference of the object itself.

      The equation, then, tell us that the relation between the energy of a body of mass m and it's momentum is not linear, as thought in Newtonian physics, but it's actually a quadratic wrt the speed of light. WRT a certain frame of reference moving at constant speed from our object, the amount of energy we need to increase its momentum by 1 (units of momentum, Kg*ms^-1 on the IS) is bigger the bigger the object's momentum is.

      The mass of an object is a constat, like the speed of light is. Talking of 'rest mass' and all that was caused by eager physicists trying to prove Newton's equations were still valid... But they are not, and telling ourselves lies won't help us understand the Universe better.

      BTW, E=mc^2 is the energy of a body of mass m on its own frame of reference; for particles that cannot have a frame reference, like photons and other particles that move at the speed of light, the relation becomes easier, as the massive term dissapears (cannot be mass as there's no proper frame of reference to define it in the first place!) E=pc (which is used a great deal in 1st quantification theories, and helps to find out through DeVroglie's relation the value of Plank's constant h).

      So E=pc is as important or even more than E=mc^2...

      BTW, the "right" way to write this is, being the tetra-momentum P^mu = (-cm, p), where mu=0,1,2,3; p is a three-dimensiona vector defined as gamma*mv (where gamma is the 1/sqrt(1-v^2/c^2) factor of Lorentz' transformations); ^ means superscript and _ subscript, and the metric tensor M^(mu nu) chosen so that the diagonal elements are time-space= (-1,1,1,1); we get that:

      E^2/c^2 = P^mu*M_mu^nu*P_mu = c^2m^2 + p^2

      which is the right formula for this case... QED

      and if we make c=1 as usual, we get that E^2 = m^2 + p^2; with frontier cases of E=m and E=p, which is easier to read and don't hide the physical meaning of the result...

    21. Re:Einstein's FULL equation by szkot · · Score: 1

      How do you know that the mass of a fast moving particle changes? Can you measure the mass directly? p = gamma*m0*v does not mean m = gamma*m0. This perhaps an interpretative difference, but it is an important one.

    22. Re:Einstein's FULL equation by Gil-galad55 · · Score: 1
      Personally, I like it best using "God's units" :

      E^2 = P^2 + M^2

      I love that sig, by the way :)

      --

      To follow knowledge like a sinking star, / Beyond the utmost bound of human thought. ("Ulysses", Tennyson)

    23. Re:Einstein's FULL equation by physman · · Score: 1

      No, Newtons second law states that rate of change of momentum is directly proportional to force, therefore F = d(mv)/dt = m.dv/dt + v.dm/dt, when the mass is constant, F = m.dv/dt = ma. But we can't use F=ma for a rocket, because the mass of the rocket changes. F=d(mv)/dt is the definition of F.

      --
      Murphy's Law of Research: Enough research will tend to support your theory.
    24. Re:Einstein's FULL equation by Anonymous Coward · · Score: 0

      It is well understood that mass terms are always the rest mass. There is no need to add the 0 subscript.

      Mass is the invariant length of the 4-momentum.

  26. Quotation from non-mathematical world by Anonymous Coward · · Score: 1, Funny

    Beauty * Brains = Constant

    1. Re:Quotation from non-mathematical world by Zilquis · · Score: 1

      You forgot one bit Its Brains * Beauty * Availability = Constant

  27. Physics/Mathematics equation top 20 by MoobY · · Score: 1

    I guess that the list of greatest equations would be completely different if polled in a mathematical community, instead of the physics community polled in the referred article. Some of the equations that are in this list, and universal to mathematics and physics (like 1+1=2 and e^i*pi+1=0) would definitely pop up in the mathematics list too, but many other differences will be easy to spot (e.g. mathematicians wouldn't have maxwell's, general relativity, gas laws and the such in their list)

    --
    --- Sigmentation Fault - Comments Dumped
  28. (Generalized) Stokes equation by Ibag · · Score: 4, Insightful

    The integral of a differential form on the boundry of a manifold is equal to the integral of the exterior derivative on the manifold itself.

    S_{dM)w=S_(M)dw

    An important special case is the fundamental theorem of calculus. Not only is this a beautiful looking theorem, but important too.

    Other special cases are the classical forms of green's theorem, stoke's theorem, and the divergence theorem.

    I dunno if its my favorite equation, but its up there.

    1. Re:(Generalized) Stokes equation by Just+Some+Guy · · Score: 2, Funny
      That's very similar to Farfegnugen's Law of Inverse Transients relating the comb structure of the polymassive decay groupings to the unthorped resident pressures:

      S_{pD0^(42e)}pi=23^ln(volume)

      Oh, crap, why don't you admit that we both just made this stuff up to sound intelligent on Slashdot?

      --
      Dewey, what part of this looks like authorities should be involved?
    2. Re:(Generalized) Stokes equation by LincolnQ · · Score: 1

      Hey. Don't dis the Stokes equation; it is real and it is very cool.

      To explain it a bit, a manifold is a 'thing with a border', and it can be manydimensional, but let's look at it in 2D. If I have a circle in the plane, this says that I can find the area in two ways -- either I can use the integral to form the area itself using a regular area integral, or I can do a line integral along the curve of the circle.

      Now, you can extend this in many different ways. Instead of simply finding the area, I could integrate some more complicated function (Ampere's Law maybe.) Or you could extend it into the third dimension -- instead of integrating inside the sphere, do a surface integral across the surface.

      Basically, it says that you can always do either the 'inside integral' or the 'boundary integral'.

      (Someone correct me if I've oversimplified somewhere)

    3. Re:(Generalized) Stokes equation by Ibag · · Score: 1

      Nah, doesn't look like you've oversimplified anything important. I suppose I could nitpick that the definition you give is a bit bad, as I would have gone for "an object similar to a curve, surface, or solid, except possibly in higher dimensions."

      I should probably have added that stokes requires a manifold with boundary (which is implicit in the fact that I take the boundry of the manifold), and that manifolds do not neccesarily have to have boundaries.

      Another small place where you have possibly oversimplified is that you can't always do an inside integral or a boundary integral. A boundary integral cannot be converted to an inside integral if there isn't some thing that you have a boundary of for which your form is defined (as an example, xdy-ydx/x^2+y^2 and a circle around the origin). Also, an inside integral cannot be converted to a boundary integral if you are not integrating a form which is the dereivative of another (an exact form).

      However, special cases where things don't hold only detract from a good explanation, so I shouldn't have brought it up. If you change always to "almost always" I will be happy!

    4. Re:(Generalized) Stokes equation by johndoe42 · · Score: 1

      Agreed.

      This one also gives the fundamental theorem of (vector) calculus, as well as much of complex analysis (where the manifold in question is a piece of the complex plane containing some poles).

      Definately beats e^i*pi + 1 = 0, since it's actually useful :)

    5. Re:(Generalized) Stokes equation by slothman32 · · Score: 1

      I haven't studied manifolds and boundaries but I know "regular" Calculus. I know a line integral and area integral. I can almost imagine manifolds. Of the two the forms from the parent I can't figure out which is the line and which the area.

      It looks like the "differential form on the boundary" is the area one and the "exterior derivative" is the line one. Similarly the " S_{dM)w," which I am guessing means the integral of wdM as I only see a capital S followed by a underscore in my browser, is the area one and the "S_(M)dw" is the line one.
      Am I correct or do I know nothing of this?

      --
      Why don't you guys have friends or journals?
    6. Re:(Generalized) Stokes equation by phyy-nx · · Score: 1
      So you're saying this is the differential strokes equation?

      Whatcho talking about?

    7. Re:(Generalized) Stokes equation by Skavookie · · Score: 1

      Not just vector calculus. The fundamental theorem you learn in single-variable calc is also a special case.

    8. Re:(Generalized) Stokes equation by Skavookie · · Score: 1

      Well, technically a manifold has to be locally Euclidean.

    9. Re:(Generalized) Stokes equation by Skavookie · · Score: 1

      MathWorld is your friend:
      http://mathworld.wolfram.com/StokesTheore m.html

      By dM the parent poster meant the boundary of M, which is often denoted by M with the partial-derivative symbol prefixed to it. So S_{dM}w is the integral of w over the boundary of M. Stokes theorem says that this is equal to S_(M)dw, the integral of dw over M.

      In the regular single variable calculus case M is an interval and dM is it's boundary (the endpoints), w is a function on M, and dw is the exterior derivative (basically the differential) of w. Written another way, if we let dw = f(x) dx and F'(x) = f(x) then the generalized stokes theorem roughly says that the sum of F(x) evaluated at each point on the boundary of the interval (i.e. the endpoints) equals the sum (integral) of f(x) dx evaluated at every point on the interval.

      In two variables M is a surface, in which case dM is the curve that forms the boundary of the surface. This gives the traditional formulation of Green's Theorem.

    10. Re:(Generalized) Stokes equation by Anonymous Coward · · Score: 0

      Spivak's Calculus on Manifolds explains all [at an undergraduate level].

      If "w" is some (n-1)-dimensional "flux" on the "surface" (boundary) of a manifold M (call this boundary @M), then Stokes' theorem says that

      Integral over @M [ w ] = Integral over M [ dw ],

      where "dw" is the "derivative" of "w". Handwaving, the surface integral of the flux equals the volume integral of the flux density, but on manifolds.

      From Stokes' theorem you get the fundamental theorem of calculus, Green's theorems, the divergence theorem, cohomology, Gauss's law, Maxwell's equations, etc.

      And yes, it definitely should be on the list.

      http://www.amazon.com/exec/obidos/tg/detail/-/0805 390219/qid=1099419037/sr=8-1/ref=pd_csp_1/102-4547 408-2044937?v=glance&s=books&n=507846
  29. Comment removed by account_deleted · · Score: 1

    Comment removed based on user account deletion

  30. Everything = 42 by marcovje · · Score: 4, Funny


    Everything = 42 :-)

    1. Re:Everything = 42 by crull · · Score: 1

      I know the story and everything but...

      consider something like this.
      6*7-0.0001 = almost everything
      how stupid is that?

      --
      this is not my signature.
    2. Re:Everything = 42 by Alranor · · Score: 1

      Actually, wasn't that:

      6*9 = 42

      (with the addendum that the creator obviously works in base 13)

    3. Re:Everything = 42 by Anonymous Coward · · Score: 1, Funny

      Wouln't that be:
      Everything = 42 - Life - Universe? =)

    4. Re:Everything = 42 by martinde · · Score: 2, Interesting

      Reminds me of a fun trick with google. Google's calculator knows all kinds of constants - "c", "pi", "e", etc. (Just put those in the standard search box and hit search and you'll see what I mean. Now you can use them in equations - "2*pi+7" or whatever.)

      Anyways, it knows this constant too:
      "the answer to life the universe and everything"

      Made me chuckle the first time I saw it...

    5. Re:Everything = 42 by Estian · · Score: 1

      Nobody writes jokes in base 13

    6. Re:Everything = 42 by kalirion · · Score: 1

      Not even pretty sad people.

    7. Re:Everything = 42 by Sentry21 · · Score: 1

      6 x 9 = 42 is my personal favourite.

    8. Re:Everything = 42 by 10100 · · Score: 0

      Actually,

      Everything != 42

      42 is the ultimate answer to the ultimate question of Life, the Universe, and Everything ;-)

    9. Re:Everything = 42 by Anonymous Coward · · Score: 0

      Fnet=ma is my favorite equation. that and DeltaU=q+w

  31. Some important ones... by lithium100 · · Score: 1

    Taylor series expansions
    Schrodinger's Equation
    Heisenberg Uncertainty Principle
    Normal Distribution Curve
    Einstein's Time Dilation and relativistic equations
    Newtons three laws and law of universal gravitation
    Fourier's transformation(s)

    1. Re:Some important ones... by Anonymous Coward · · Score: 0

      p = SU(G(SU))

      Gödel's incompleteness theorem

  32. actually this is on topic, strangely enough by themusicgod1 · · Score: 1

    thank you sir. for those still doubtful, check out my sig. Specifically, this section.

    --
    GENERATION 26: The first time you see this, copy it into your sig on any forum and add 1 to the generation.
    1. Re:actually this is on topic, strangely enough by Anonymous Coward · · Score: 0

      I find it quite cool that you mention your WPM in your resume - been quite a while since I saw anyone do it :-)

      (meant that as a compliment, just in case you misinterpret)

  33. Actually... by yoshi_mon · · Score: 4, Insightful

    If it wasn't for this equation, your cell phone wouldn't work.

    If it wasn't for the laws of nature things wouldn't work. The mathematical formulas are our way of expressing them.

    --

    Really, I know what I'm doing...Ohhhh, look at the shiny buttons!
    1. Re:Actually... by beaverfever · · Score: 2, Informative

      it wasn't for this equation, your cell phone wouldn't work.

      If it wasn't for the laws of nature things wouldn't work. The mathematical formulas are our way of expressing them.


      Mathematical formulas indicate an understanding of such laws, so without that understanding, your cell phone wouldn't work.

    2. Re:Actually... by Phekko · · Score: 4, Insightful

      Mathematical formulas indicate an understanding of such laws, so without that understanding, your cell phone wouldn't work.

      I believe there are quite a few inventions that have been stumbled upon without any understanding about mathematical formulas whatsoever. Amazing what can be accomplished with the old trial and error method =)

      --

      Sigs for Nerds. Sigs that Matter.
    3. Re:Actually... by Anonymous Coward · · Score: 0

      Mathematical formulas indicate an understanding of such laws, so without that understanding, your cell phone wouldn't work.

      Oh if only this reasoning was true!

      The large number of ignorant people on the planet would easily offset all our real problems.

    4. Re:Actually... by Anonymous Coward · · Score: 0

      Nature is more dependant on math than math is on nature. If you don't realize this, you need to go back to school.

    5. Re:Actually... by Rich0 · · Score: 4, Insightful

      e^i*pi=-1 isn't a law of nature.

      It is a mathematical relationship which is completely abstract - none of those values are physical quantities, although all of them are used in other physical equations.

      In theory an alien in a completely different universe could come up with the same formula.

      Think about it - e is related to the integral of 1/x on a flat plane - which doesn't exist in real life. i is the square root of -1, which is about as abstract a concept as you'll ever come up with - it certainly doesn't correspond to any physical quantity (unless you define a physical system using complex coordinates for the sake of convenience). Pi is a number which is very useful in practical measurements, but which can be described completely in the abstract.

      In any case, an equation like Euler's formula reflects our understanding of mathematics in general more than it reflects our knowledge of any particular physical process.

    6. Re:Actually... by dwbassett42 · · Score: 5, Funny

      This difference in views is similar to a fundamental difference between engineers and physicists: Engineers feel their equations are a reasonable approximation of reality, and physicists feel that reality is a reasonable approximation of their equations. And mathematicians? They see no relation between the two. ;)

    7. Re:Actually... by jpnews · · Score: 2, Funny

      Mathematical formulas indicate an understanding of such laws, so without that understanding, your cell phone wouldn't work.

      Without lamps, there'd be no light.

    8. Re:Actually... by Smidge204 · · Score: 4, Funny

      Nonono, any researcher will tell you that. They just want to cover up the TRUTH. Those complex mathematical formulas are actually mystical runes that describe ancient spells. The formulas themselves DO make your phone work!

      =Smidge=

    9. Re:Actually... by Anonymous Coward · · Score: 2, Insightful

      Nature is more dependant on math than math is on nature. If you don't realize this, you need to go back to school.

      Rubbish.

      Nature existed for billions of years before anybody thought about math.

      Math is only an abstract construct that doesn't have independent existence.

    10. Re: Actually... by trip11 · · Score: 1

      There are a few places where using i makes sense. Albeit it will probably get squared at some point. I'm thinking in quantum you can use a potenial of the form V= A+Bi where B is an absorbsion so that it 'sucks up' probiblility from the wave function. Or anytime you can talk about forier transforms etc you can wiggle i in. But generally yeah I supose they are pretty contrived however sometimes you just need the concept that a number squared is negitive.

    11. Re:Actually... by rsidd · · Score: 4, Interesting
      i is the square root of -1, which is about as abstract a concept as you'll ever come up with - it certainly doesn't correspond to any physical quantity (unless you define a physical system using complex coordinates for the sake of convenience).

      Quantum mechanical wavefunctions are complex. You could define them as two real wavefunctions and work out the appropriate algebra, but it's exactly complex algebra. So i could correspond to the phase difference of two wavefunctions, which would be observable via interference effects.

      Not disagreeing with what you're saying though -- the equation is fundamental mathematics, independent of the physical universe, it doesn't make sense to imagine an "alternative universe" where it doesn't apply.

    12. Re:Actually... by quetzalc0atl · · Score: 2, Interesting

      what you have stated so plainly may not be so plain. you are taking the philosophical standpoint that mathematics is nothing more than a model of physical reality.

      most platonists would differ. in their view, mathematics has an existence all to it's own, and transcends the physical universe. they claim that their equations have an intrinsic existence of their own, regardless of their expression or discovery.

      it is interesting to note that every great civilization that has endured for hundred or thousands of years was mathematically advanced. mathematical knowledge is directly proportional to ones power.

      it is also incredible that many mathematical discoveries have preceded the discoveries of physical laws which use those mathematics....

    13. Re:Actually... by Anonymous Coward · · Score: 0

      "In theory an alien in a completely different universe could come up with the same formula."

      ... and perhaps aliens in our own Gallaxy could have "fancy cell phones" without that formula!

      It is just ONE way to represent/think about an abstract entity. It ISN'T the ONLY way.

    14. Re:Actually... by why7whynot1 · · Score: 1

      Well, assuming that we are Turing machines (which seems probable) then we could say that a mathematical formula is not our way of expressing reality, but actually our way of perceiving it (since all possible thoughts are then just mathematical relations). Since we can never see anything but the mathematical formula, trying to differentiate between reality and the formula becomes fairly meaningless.

    15. Re:Actually... by Suidae · · Score: 1

      In theory an alien in a completely different universe could come up with the same formula.

      True, but I think perhaps you underestimate how truely alien alternate realities with radically different physical laws could be.

    16. Re:Actually... by Mikkeles · · Score: 4, Informative
      'As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.'

      - Albert Einstein, Sidelights on Relativity

      --
      Great minds think alike; fools seldom differ.
    17. Re:Actually... by rubmytummy · · Score: 1

      Weeeell ... If the alien lived in a universe more gravitically interesting than our own, his pi might have a different value from ours. Wouldn't that make things a bitch.

    18. Re: Actually... by freqres · · Score: 1

      Calculating out electrical impedances when you have the R, L and C is also a good use for i, but in my EE textbooks they usually use j notation instead of i. I do agree with the original poster though that i is just an abstract math concept though. It just happens that using it to represent and manipulate 2-D vectors comes in handy.

      --
      Rampant Ninja related crimes these days...Whitehouse is not the exception
    19. Re:Actually... by freqres · · Score: 2, Funny

      I think I need a new reel of tape in my head then. The one I have now seems to only deal with beer and boobies.

      --
      Rampant Ninja related crimes these days...Whitehouse is not the exception
    20. Re:Actually... by psbrogna · · Score: 5, Funny

      For example, MS Windows.

    21. Re:Actually... by Vintermann · · Score: 2, Funny

      It's what I always said, maths is in fact magic.

      It would be cool with a game like final fantasy where spells were named after mathemathical concepts.

      Quick! Do a Laplace transformation and invoke the Jacobi symbol!

      --
      xkcd is not in the sudoers file. This incident will be reported.
    22. Re:Actually... by Anonymous Coward · · Score: 0

      Yes. But. It's likely that if this were not known, that humans would lack the ability to make a cell phone.

    23. Re:Actually... by rjshields · · Score: 1

      i is the square root of -1, which is about as abstract a concept as you'll ever come up with

      Negative numbers are pretty abstract in themselves. If I have 5 apples, you can't take away 10 because I only have 5. I can't possibly have -5 apples, because the fewest I can have is 0. So it's not surprising that the square root of a negative number is hard to fathom.

      --
      In this world nothing is certain but death, taxes and flawed car analogies.
    24. Re:Actually... by Anonymous Coward · · Score: 0

      " i is the square root of -1,"

      i is better defined as the relation: i * i = -1

    25. Re:Actually... by shokk · · Score: 1

      Dude, you still owe me 5 apples. Don't give me that "but I only have 5 apples" business. Vinny will be by later to show you what happens to deadbeats.

      --
      "Beware of he who would deny you access to information, for in his heart, he dreams himself your master."
    26. Re:Actually... by Mikkeles · · Score: 2, Interesting
      'Mathematical formulas indicate an understanding of such laws, ...'

      Another view, that I find interesting, and am tempted to subscribe to, is:
      Physics is mathematical not because we know so much about the physical world, but because we know so little; it is only its mathematical properties that we can discover. - Bertrand Russell
      --
      Great minds think alike; fools seldom differ.
    27. Re:Actually... by Superfreaker · · Score: 1

      I believe there are quite a few inventions that have been stumbled upon without any understanding about mathematical formulas whatsoever.

      Exactly! Like the Easy Bake Oven.

      Captain Murphy tell us that the secret ingredient is LOVE!

    28. Re: Actually... by Anonymous Coward · · Score: 0

      bj, where the j is imaginary for an ee? how appropriate.

    29. Re:Actually... by roystgnr · · Score: 1

      Not disagreeing with what you're saying though -- the equation is fundamental mathematics, independent of the physical universe, it doesn't make sense to imagine an "alternative universe" where it doesn't apply.

      You can imagine an "alternative universe" where the math is true, but doesn't correspond to anything physical. In our universe, for example, if you're traveling 2 km/h and you throw a ball ahead of you at 2 km/h, relativity says the ball will be moving at 3.9999 (add another couple dozen 9's) miles per hour. Make those effects more obvious and make all the other laws of physics that weird and perhaps you'd get a universe whose inhabitants think of "2 + 2 = 4" as just a neat theoretical abstraction.

    30. Re:Actually... by cellocgw · · Score: 1

      >>>If it wasn't for this equation, your cell phone wouldn't work.

      >>If it wasn't for the laws of nature things wouldn't work. The mathematical formulas are our way of expressing them.

      >>Mathematical formulas indicate an understanding of such laws, so without that understanding, your cell phone wouldn't work.


      So far so good: nobody has started posting postmodern philosophical claims that in fact the laws of nature only exist after we decide they do. :-)
      I think I might phrase the quoted comments as: "Without our ability to form mathematical models we would be unable to design complicated hardware that actually performed the functions we desired."

      --
      https://app.box.com/WitthoftResume Code: https://github.com/cellocgw
    31. Re:Actually... by cellocgw · · Score: 1

      Negative numbers are pretty abstract in themselves.
      Heck, so are nonnegative numbers. Can you show me a "two"? No. You can show me a numeral "2," or two of some object. I'll grant it's easier to demonstrate a quantity associated with two than a quantity associated with -2 or 2i, but there are plenty of mathematicians who have the ability to comprehend the latter quantities just as easily as plain old 2.

      --
      https://app.box.com/WitthoftResume Code: https://github.com/cellocgw
    32. Re:Actually... by Anonymous Coward · · Score: 0

      Vinny can kiss my arse, dude.

    33. Re:Actually... by rjshields · · Score: 1

      So you're saying that a positive number can be easily thought of as have a psysical presence, but a negative number cannot. Thanks for re-iteraing my point.

      --
      In this world nothing is certain but death, taxes and flawed car analogies.
    34. Re:Actually... by Anonymous Coward · · Score: 0

      In the same way, can you show me blue? You can show be a blue ball or the blue sky, but can you show me blue?

      Numbers are really properties that we ascribe to sets of objects in the same way that colors are properties that we ascribe to individual objects. The really amazing revelation is the abstraction of the property from the object. Once you realize that putting two apples together with two other apples is the same as putting two fingers together with two other fingers, it's an inevitable logical step to mathematics.

      To get back to the blue, concepts like ultraviolet would be just as abstract as negative numbers, being the natural extension of observable properties (in this case, color).

    35. Re:Actually... by mdemirha · · Score: 1

      Actually, "i" is commonly used to differentiate between two different dimensions in the physical world - so, it can be seen as a law of the nature in many cases.

    36. Re:Actually... by Frodo420024 · · Score: 1
      e^i*pi=-1 isn't a law of nature.

      That certainly depends on your definition of 'nature'!

      If you check out this years Nobel Price winners (it's about Quarks and the Strong force in atomic nuclei, Quantum ChromoDynamics, QCD), you'll find that nature, at its innermost core, is described in terms of waves and quite advanced mathematics. The deeper you examine the nature of space and matter, the more mathematical and abstract it gets.

      It's quite fortunate that it simplifies to Newtonian physics in most everyday situations, or it'd be a nightmare to make stuff like cars etc. work.

      Eulers Formula is a reminder that the Universe is a much more magical place than we usually think of. With all due respect for the others, this one wins my heart.

      --
      I'm in a Unix state of mind.
    37. Re:Actually... by rsidd · · Score: 2, Insightful
      Make those effects more obvious and make all the other laws of physics that weird and perhaps you'd get a universe whose inhabitants think of "2 + 2 = 4" as just a neat theoretical abstraction.

      Nope. In that universe, if they added two apples to two apples, they'd still get four apples. Velocities may not be additive but other things would be. Even in our universe: it's not really flat (Euclidean), and the earth isn't flat either, but both are flat at small scales: you won't think about the curvature of the earth while building your house. So idealisation can still be useful (and of course, if you want to deal with curvature and relativity, mathematics can help you out there too).

    38. Re:Actually... by syynnapse · · Score: 1

      i think the most appropriate equation for /. is

      u = n

      where n is "nerd".

      --

      System.out.println(syynnapse.getSig());

    39. Re:Actually... by Anonymous Coward · · Score: 0

      2 km/h + 2km/h equals how many miles per hour?

    40. Re:Actually... by Listen+Up · · Score: 1

      There is a complete difference between stumbling onto a physical law or process and completely and fundamentally understanding it. Without Mathematics, all things in this universe would be known only by observation without understanding.

    41. Re:Actually... by wmaker · · Score: 1

      i should never be defined as 'the square root of -1' as you put it. Instead, it should be considered the solution of x^2 = -1.

      for example using sqrt(-1) instead of i returns this

      -1 = i * i = sqrt(-1) * sqrt(-1) = sqrt(-1 * -1) = sqrt(1) = 1

      does -1 = 1?

    42. Re:Actually... by Rich0 · · Score: 1

      By the same logic:

      sqrt(-2)*sqrt(-2) = sqrt(-2 * -2) = sqrt(4)=2

      However, this is not true.

      sqrt(a)*sqrt(b) does not necessarily equal sqrt(a*b).

      You are probably right that the official definition is probably the principal root of x^2=-1 (remember, there are two roots).

    43. Re:Actually... by Rich0 · · Score: 1

      Perhaps. However, keep in mind that when the Schrodinger equation was invented the physicists didn't have to spend much time trying to solve the thing. It turns out that some guy solved it a few hundred years beforehand - as an abstract math problem. It had nothing to do with physics at the time.

      We've probably already solved the GUT for a million possible universes. Now, if only we could come up with one for our own...

    44. Re:Actually... by wmaker · · Score: 1

      NO! you are wrong, by definition and math law, the sqrt(a) * sqrt(b) = sqrt(a*b)
      try it out with a number right now! you got modded up for complete bullshit.

    45. Re:Actually... by Rich0 · · Score: 1

      Uh, check out Wikipedia... The first sentence in the properties section indicates that this relationship is only valid for positive values of a and b.

      (a*b)^x = a^x * b^x is certainly not true by definition. It does happen to be true for many values of a,b, and x. To determine the conditions under which it is true, you'd need a proof.

      I don't have a math book handy, but I'm fairly sure that the disclaimer for positive values of a and b was specifically added to address the problem you propose.

    46. Re:Actually... by cloudmaster · · Score: 1

      I think we were talking about inventions that actually work... Sumbling on to ideas that don't quite work isn't really a great feat. :)

    47. Re:Actually... by rjshields · · Score: 1

      I see your point exactly - that numbers in general - both positive and negative - are an abstract concept. My point is that human brain (well mine anyway) has a harder time justifying the existence of negative numbers because they can't be represented physically, to the point that people devise mathematical equations to justify their existence.

      --
      In this world nothing is certain but death, taxes and flawed car analogies.
    48. Re:Actually... by texaport · · Score: 1

      Einstein said ENERGY=MASS

      e=m*c*c with a constant squared being a constant
      e=km where the new constant merely adjusts for units
      e=m

    49. Re:Actually... by Anonymous Coward · · Score: 0

      If you use the real field, then you will not get real numbers for the physical measurements. You must use the complex field to get real valued eigen values for the hermitian operators.

    50. Re:Actually... by Anonymous Coward · · Score: 0

      So you're saying that a positive number can be easily thought of as have a psysical presence, but a negative number cannot.

      But it can.

      If I have 5 apples, how many apples do I need to add to get 3 apples?

    51. Re:Actually... by srleffler · · Score: 1
      Quantum mechanical wavefunctions are complex. You could define them as two real wavefunctions and work out the appropriate algebra, but it's exactly complex algebra. So i could correspond to the phase difference of two wavefunctions, which would be observable via interference effects.

      There is an easier and better way. Quantum mechanical states are points in Hilbert space. All of quantum mechanics can be reduced to mathematics in Hilbert space, eliminating the need for wavefunctions. Any property of a quantum mechanical state that can actually be observed or measured can be represented by a real number (or a collection of real numbers). Mathematically, every possible observation can be represented by an operator which has real eigenvalues.

      Wavefunctions are a convenient abstraction that allows us to apply our intuitive understanding of waves to solving quantum problems.

    52. Re:Actually... by Anonymous Coward · · Score: 0

      And mathematicians? They see no relation between the two.

      I don't get this part.

    53. Re:Actually... by Anonymous Coward · · Score: 0

      Here: Somebody put this in a formula:
      Southerners + Yankee Credit Card Banks = Permanent Poverty for Southerners.
      Here's another: Money = 0 then Print-your-own $ using Credit Cards. (simple concept, tried by everyone, needing a nice mathematical formula to express it.)

    54. Re:Actually... by Anonymous Coward · · Score: 0


      Uh, check out Wikipedia... The first sentence in the properties section indicates that this relationship is only valid for positive values of a and b.

      (a*b)^x = a^x * b^x is certainly not true by definition. It does happen to be true for many values of a,b, and x. To determine the conditions under which it is true, you'd need a proof.


      Sorry, dude, but this is why wikipedia is a piece of shit. The most basic and fundamental definition of "square root" has no restriction of being nonnegative. A square root, or radical of x is classically defined as a number n such that n^2 = x. Nothing more.

      Now, when square root is written in prose as in "the square root of x is y" it is usually taken to mean a function that gives the "principal square root". Furthermore, the radical symbol is assumed to be a *function* where the range is the principal square root.
      This means that the wmaker wanker is indeed wrong if we assume that "sqrt" is a standin for the radical sign/function. sqrt(x)sqrt(y) = sqrt(xy) , for positive values of x and y ONLY.

      So yes, while you are correct, I think the wikipedia article is not general, and should take the time to explain the whole thing for an entry as general as "square root". It just confuses people.

      And no, I don't think the distinction is overly pedantic. There is clearly an important distinction between the concept and definition of a square root, and the usage of the term "square root" and a funny symbol that happens to be called the "square (or n) root sign".

    55. Re:Actually... by Anonymous Coward · · Score: 0

      I thought it over, now I get it.. I think.

    56. Re:Actually... by Rich0 · · Score: 1

      This kind of reminds me of the long explanation in the manual of why when you enter -27 into an HP48 calculator and ask for the cube root, you don't get the -3 that most pre-trig math students would tend to expect.

      For those not following, or who didn't have great trig classes, x^3=-27 has three roots - one of which is the easily understood -3, and the other two which are complex. All three are of the form -3(cos T + i sin T), where T = pi +- 2/3pi. The smallest positive value of T is 1/3pi, and this is the principal cube root, which is what the HP48 returns. (You can visualize all of this by looking at roots as polar vectors. An n'th root of a number has n solutions, which are arrayed at equal angles around the origin (ie they are separated by an angle of 2pi/n).) My math is a bit rusty so I forget the appropriate general formulas...

      I'll admit to not being a math major, and I certainly don't apply it nearly as much now as I did in school. However, I did minor in math and anytime that somebody more learned than I wants to point out one of my mistakes I'm happy to listen...

    57. Re:Actually... by Rich0 · · Score: 1

      Doh - that is +3(cos T + i sin T)!

    58. Re:Actually... by Jon_S · · Score: 1

      Aren't the tops of the towers of the Verrazano Narrows Bridge 2 inches further apart than at the base? OK, so the VN bridge isn't a house.

    59. Re:Actually... by Anonymous Coward · · Score: 0

      Precisely incorrect. What you call 'real life' is in fact merely an illusion, it is an artificial abstract mental construction you have created that is as inaccurate as it is unreal.

      Whereas "e^i*pi=-1" is most definitely a law of nature. All mathematical truths are part of nature. How else could we discover them?

    60. Re:Actually... by rsidd · · Score: 1
      There is an easier and better way. Quantum mechanical states are points in Hilbert space. All of quantum mechanics can be reduced to mathematics in Hilbert space, eliminating the need for wavefunctions.

      Quantum mechanical states are vectors in a Hilbert space. And it's still a complex space (ie, over a complex scalar field). A wavefunction is a representation of a vector in the Hilbert space, using a coordinate basis. If two wavefunctions are out of phase by pi/2 (ie, a factor of i) in the coordinate basis, they are in your abstract Hilbert space, too.

    61. Re:Actually... by nova20 · · Score: 1

      Mathematical formulas indicate an understanding of such laws, so without that understanding, your cell phone wouldn't work.

      So you're saying that if I didn't know a mathematical representation of heat loss/gain within a system that an ice cube won't cool my cola as it melts?

      -nova20

    62. Re:Actually... by beaverfever · · Score: 1

      Mathematical formulas indicate an understanding of such laws, so without that understanding, your cell phone wouldn't work.

      So you're saying that if I didn't know a mathematical representation of heat loss/gain within a system that an ice cube won't cool my cola as it melts?


      No, I'm saying that if you didn't know a mathematical representation of heat loss/gain within a system that you wouldn't be able to build a reliable mechanical refrigerator to cool your cola.

    63. Re:Actually... by goodydot · · Score: 1

      Not really. MS Windows missed out on the 'trial' part.

  34. an old favourite by Anonymous Coward · · Score: 2, Funny

    b4i (square root)u ru/16

  35. OBLIGATORY: by marktaw.com · · Score: 1, Funny

    Life, The Universe & Everything = 42

    1. Re:OBLIGATORY: by SamSim · · Score: 1, Funny

      6x9=42

    2. Re:OBLIGATORY: by dizee · · Score: 1
      6x9=42
      you must work for NASA...
    3. Re:OBLIGATORY: by Anonymous Coward · · Score: 0

      This is at the end of the first book: stranded on prehistoric Earth, Arthur and Ford decide to try to extract the Question (or a version of it) from Arthur's brain by using his subconscious to modulate a random process: pulling Scrabble letters out of a bag. To their surprise, it works, producing the question "What do you get if you multiply six by nine?"

      "Six by nine. Forty-two. I always said there was something fundamentally wrong with the Universe" said Arthur.

    4. Re:OBLIGATORY: by markbark · · Score: 1

      But 6 times 9 DOES equal 42..... in base 13.

      --MAB

    5. Re:OBLIGATORY: by marktaw.com · · Score: 1

      Actually, both the question and the answer can't be known in the same universe, or else the universe would self destruct and something even more bizarre would replace it. Some people think this has already happened.

  36. Big Constant? by Anonymous Coward · · Score: 0

    I have a first class with honours degree in electronics sytems and I modelled for a short time in my youth!

  37. 0+2=1 by Dr.Opveter · · Score: 0

    i like that equation best when it comes to music (nomeansno)

    --
    Sample this!
  38. One my calc teacher showed me by lewger · · Score: 5, Funny

    I always liked this one that my calc teacher says he saw once on a students paper
    Sin x / n = 6
    The logic of this was that the n on the bottom cancelled out the n on the top so the result was Six. Oh well I laughed when I was shown it.

    1. Re:One my calc teacher showed me by Jesrad · · Score: 1

      Nice :) It works in french too.

      --
      Maybe we deserve this world ?
    2. Re:One my calc teacher showed me by stud9920 · · Score: 0

      you won't understand this one, but cheval/oiseau= vachel/oiseau = bete a pis l / bete a ailes = beta pi l / beta l = pi. Therefore horse/bird=pi

    3. Re:One my calc teacher showed me by Anonymous Coward · · Score: 0

      Ergo,

      sec x / c = sex.

      You're bound to get laid in the maths dept with that one.

    4. Re:One my calc teacher showed me by pommiekiwifruit · · Score: 1

      b 4i \/u RU/16

    5. Re:One my calc teacher showed me by geighaus · · Score: 1

      in the same vein cos x / cot x = cos / cot = s/t = v (which is the formula of velocity)

  39. I like this one too by MachDelta · · Score: 1

    Though its more famously attributed to in words, it works in math too:

    Intelligence * WorldPopulation = Constant

    1. Re:I like this one too by Anonymous Coward · · Score: 0

      I just they must have been fucking brilliant back in the stone age...

    2. Re:I like this one too by MachDelta · · Score: 1

      Sure! Just think of what all we discovered back then: Sex. Fire. Wheels. Pointy things to catch food with. You can blather on all you want about the theory of relativity, but where would we be without those things our ancestors invented? We'd be screwwed! Or rather, we wouldn't be... screwwed... erm. Yeah, nevermind that last part.

  40. ... and then there was light by beuges · · Score: 1
    1. Re:... and then there was light by KjetilK · · Score: 1

      Heh, I have this on three different t-shirts... Guess that makes me a physics geek... :-) But it is much prettier on vector form, only four equations...

      --
      Employee of Inrupt, Project Release Manager and Community Manager for Solid
    2. Re:... and then there was light by Gil-galad55 · · Score: 1

      Best of all in relativistic tensor notation -- only 1! (Well, up to your choice of gauge, anyway...) Cheers!

      --

      To follow knowledge like a sinking star, / Beyond the utmost bound of human thought. ("Ulysses", Tennyson)

    3. Re:... and then there was light by KjetilK · · Score: 1

      Yeah, that's right! Funny, I'm actually wearing one of those t-shirts, but I didn't notice when I put it on this morning... :-)

      --
      Employee of Inrupt, Project Release Manager and Community Manager for Solid
  41. rigid polyvinyl chloride aka PVC by Anonymous Coward · · Score: 0

    3600/sec. per part*length of part/12000*MFT=lbs/hr

  42. Distribution of answers by skraps · · Score: 1
    The most normal answer:
    integral(e^(-(x^2)/2),x)/sqrt(2*pi)
    --
    Karma: -2147483648 (Mostly affected by integer overflow)
  43. Worst equation ever by shoppa · · Score: 1
    x = ( -b +/- sqrt(b^2-4ac) )/2a

    Somehow manages to take the beauty of a quadractic curve and turns it into a grunge problem.

    1. Re:Worst equation ever by SamSim · · Score: 1

      You should try the general formula for the solutions of a cubic equation. Or how about the quartic?

      Once you get to the quintic (where the maximum power of x is 5) you find there is no general solution, which quite frankly comes as a relief...

    2. Re:Worst equation ever by slothman32 · · Score: 1

      I've "proved" the cubic. But what I'm trying to do it put the answer, unfortunately very long, back in for x and solve it that way. I started but ended up with a a1*root(b1) + a2*root(b2)... with 6 terms, cube roots, and all equaling a complex function on the right. It's really hard to cube the roots away to cancel the terms. I am starting with squareroot(a1) + squareroot(a2) = c and going from there.
      I doub't I'll ever even get to the quartic one as that requires a cubic in the process.

      --
      Why don't you guys have friends or journals?
  44. Re:Submitter and Parent are stupid by pD-brane · · Score: 3, Informative

    No, everybody is correct.

    The only thing is that schematix (grandparent) misread the Pi as a 'n', which look very similar, indeed (on my screen anyway).

  45. y = r^3/3... har-de-har-har! by Anonymous Coward · · Score: 2, Funny

    From the Simpsons episode, "Bart the Genius"...

    Teacher at gifted school:
    So y = r^3/3 and if you determine the rate of change in this curve correctly, I think you will be pleasantly surprised.

    [The Class laughs. Bart looks confused.]

    Teacher:
    Don't you get it, Bart?
    Derivative dy = 3r^2 dr/3, or r^2 dr, or r dr r. Har-de-har-har!
    Get it?

  46. the fundamentals by Anonymous Coward · · Score: 0

    what no S = k.ln(W) ?

  47. khinchin's constant by harlows_monkeys · · Score: 2, Interesting
    For almost all real numbers r, let {Pn/Qn} be the sequence of convergents of the continued fraction expansion of r. Then limit as n goes to infinity of Qn^(1/n) exists and is equal to exp(pi^2/(12 ln 2)).

    That's my favorite.

    I used to even use "exp(pi^2/12ln2)" as my name in Quakeworld.

    1. Re:khinchin's constant by doru · · Score: 1

      Not exactly, see here for the expression of K (eq. 12).

    2. Re:khinchin's constant by harlows_monkeys · · Score: 1
      Not exactly, see here for the expression of K (eq. 12)

      See eq 15. The one I'm talking about (the limit of Qn^(1/n)) is exactly exp(pi^2/(12ln2)). They call it the Khinchin-Levy constant at Mathworld, but I've seen it called just the Kninchin constant. The one in eq 12 is the limit of the geometric mean of the paritial quotients of the continued fraction.

  48. Re:Submitter and Parent are stupid by pD-brane · · Score: 1

    Oh sorry, I only RTFA... the submitter (sgant) was the one misreading the pi.

  49. 'e' is for "cool formula" by Anonymous Coward · · Score: 1, Interesting

    = 1/0! + x/1! + x^2/2! + x^3/3! + x^4/$! + ...

  50. Google calculator by Knx · · Score: 3, Funny

    If you don't have a math tool handy, you can use the Google calculator to check some of the equations mentioned here. For instance:

    sqr(-1)
    e^(i.pi)+1
    1+1

    That is, if you're suspicious...

    --
    The problem with Slashdot memes is that YOU INSENSITIVE CLOD!
  51. Use the (HTML) source, Luke! by eric.t.f.bat · · Score: 2, Informative

    It's OK to use HTML on a website, you know. I suggest:

    <i>e<sup>i&pi;</sup> - 1 = 0</i>

    ... which will work nicely in most browsers.

    --
    I have discovered a truly remarkable .sig block which this margin is too small to conta
    1. Re:Use the (HTML) source, Luke! by sgant · · Score: 1

      Ok, let's give it a go here on /.

      Here it is, exactly as you posted:

      ei - 1 = 0

      What happened to the pi? Is this what you mean?

      --

      "Leo Fender was in a 'state of grace' when he designed the Stratocaster." -- Paul Reed Smith
  52. The only math equasion I ever liked... by Anonymous Coward · · Score: 1, Funny

    x / 0 = math sucks

  53. Congratulations, A Squared Equals B Minus One by YOU+LIKEWISE+FAIL+IT · · Score: 1

    ... You are the Equation of the week. ( I wish I could find the Achewood cartoon this is from, so here's link to the T-Shirt instead. )

    --
    One god, one market, one truth, one consumer.
    1. Re:Congratulations, A Squared Equals B Minus One by Ravagin · · Score: 1

      My first thought too, but I couldn't find it either. Reminds me of when the boys gave microsoft word an award, though

      --

      Karma: T-rexcellent.

  54. Exp(2*i*pi*n)-1=0 by mu22le · · Score: 1

    this equation holds if n belongs to the integears set.

    1. Re:Exp(2*i*pi*n)-1=0 by mu22le · · Score: 1

      Sorry it was:
      Exp(2*i*pi*n)+1=0
      am so stupid.

      By the way this equation become the one posted in the article for 2pi=1 wich is a choice I always endorsed.

  55. Energy stored... by tagishsimon · · Score: 1, Funny

    I'd have E=0.5mv^2 rebated into every car steering wheel in the land. And maybe a nice E display on the dashboard.

    1. Re:Energy stored... by Professeur+Shadoko · · Score: 1

      That should have been modded as 'insightful', rather than 'funny'.
      I'm quite sure some people would get scared by seeing their energy (potential of destruction) growing that much faster (quadratively) than their speed, with an 'E' display on the dashboard.

  56. 1+1=10 by notany · · Score: 5, Funny


    There are 10 kinds of people: those who understand binary and those who don't.

    --
    Dyslexics have more fnu.
    1. Re:1+1=10 by Ziviyr · · Score: 1

      ...And those who count from zero.

      --

      Someone set us up the bomb, so shine we are!
    2. Re:1+1=10 by terrymaster69 · · Score: 2, Interesting

      There is a department store here in Japan called 0101 (Marui-marui) - when I first got here, I wasn't sure what to call it, and the geek in me asked somebody, what do they sell at 5? (10...) Needless to say, that's only funny to one of the 10 types of people.

    3. Re:1+1=10 by Anonymous Coward · · Score: 0

      What about the corollary to that?

      There are 10 kinds of people in the world: those who understand trinary, those who don't, and those who think it's binary.

    4. Re:1+1=10 by juhaz · · Score: 2, Funny

      How about this instead:

      There are 10 kinds of people in the world:
      Those who understand quaternary, those who don't, those that think it's binary or ternary, and then there's are the ones who insist on making stupid jokes about numeric systems.

    5. Re:1+1=10 by 216pi · · Score: 2, Funny

      and what are the other eight?

    6. Re:1+1=10 by Soldrinero · · Score: 1

      There are 11 kinds of people: those who understand binary, those who don't, and those who get the joke.

      --
      I would rather be killed by a terrorist than enslaved by my government.
    7. Re:1+1=10 by Drakonian · · Score: 1

      Whoosh. Everyone can recognize that sound right?

      --
      Random is the New Order.
    8. Re:1+1=10 by muzik · · Score: 1

      Timmy: "Mom I need you to sign this note saying i did 100 push ups today"
      Mom: "But timmy, I only saw you do 4!!"
      Timmy: "Ahh mom, we need to teach you about binary!!"

  57. Point nine recurring equals one by SamSim · · Score: 2, Interesting

    Point nine recurring equals one.

    1. Re:Point nine recurring equals one by Haydn+Fenton · · Score: 1

      For those who dont get...

      To prove 0.9 recurring = 1, we will multiply 0.9 recurring by 10, and take 0.9 recurring away, in effect multiplying it by 9 (for displaying purposes take .9r to mean .9 recurring):

      1) 0.9r * 10 = 9.9r

      2) 0.9r * 1 = 0.9r

      3) 9.9r - 0.9r = 9.0

      Ok, so we multipled 0.9r by 10 to get 9.9r.
      Then we multipled 0.9r by 1 to get 0.9r.
      Then we took one occurance away from the other 10, which would leave us with 9 times 0.9r.
      Since we took away 0.9r from 9.9r, the whole set of recurring numbers cancell eachother out, and we are left with the answer 9.0, so if we divide that answer by 9, we will get the answer to what 1 * 0.9r is, which turns out to be 1... so there you have it, 0.9r = 1.

      If you haven't seen this before and are feeling conned, try it out with other numbers, it's the same rule.

    2. Re:Point nine recurring equals one by fatphil · · Score: 1

      "If you haven't seen this before and are feeling conned, try it out with other numbers"

      The "proof" is in some ways nonsense. It lets you "prove" 1+2+4+8+16+.... = -1

      Let S = 1+2+4+8+16+...
      1+2*S = 1+(2+4+8+16+32+...)
      So S = 1+2*S
      => S = -1

      The correct proof is to show that for any finite quantity, delta, the value of the expression is closer to 1 than delta. (Note, that is ambiguously worded, but English is lousy for mathematical formality.)

      FP.

      --
      Also FatPhil on SoylentNews, id 863
  58. and another... by Anonymous Coward · · Score: 0

    1 + 1 = A window ;-)

  59. Holiday Equation by Anonymous Coward · · Score: 0

    OCT 31 = DEC 25.

    That's why geeks always confuse Halloween and Christmas.

    Wokka wokka wokka!

  60. A couple of my favorites by kevinatilusa · · Score: 1

    1-1/2+1/3-1/4+1/5-...= ln(2)
    1-1/3+1/5-1/7+1/9-...=Pi/4

    These can be gotten from plugging x=1 in the taylor series for ln(1+x) or arctan(x), but require a fair bit of proof that the series actually converge to what you think they do. It's amazing that series that look so alike can get you pi on one hand and logs on the other!

    On the other hand, for sheer drop-your-jaw-in-awe-ness it's hard to beat some of the formulas from Ramanujan's notebooks (see example #5 at http://www.cut-the-knot.org/do_you_know/fraction.s html/ for a couple examples)

    1. Re:A couple of my favorites by gowen · · Score: 1

      I like the fact that the convergence of those is dependent on the order of the terms. If I change the order, I can make them sum to any damn thing I like.

      --
      Athletic Scholarships to universities make as much sense as academic scholarships to sports teams.
  61. Bayes' Theorem! by Eliezer+Yudkowsky · · Score: 1

    Two words: Bayes' Theorem.

    Link goes to an excruciatingly gentle introduction to what this whole Bayesian thing is about, and why your friends seem to think it's so important... but I'll go ahead and spoil the ending, and say that Bayes' Theorem is, in a sense, the underlying equation of science itself; it tells you what constitutes "rational evidence" and exactly how much evidence it is, in which direction.

    F=MA is a beautiful equation, don't get me wrong - but can it compare to the equation that describes how scientific theories are confirmed or falsified?

    --
    Planetary death rate: 150,000 lives per day. End the slaughter
    1. Re:Bayes' Theorem! by DavidHumus · · Score: 0, Offtopic

      I agree, even if it's more properly known as "Bayes's Theorem" - see http://www.bartleby.com/141/strunk.html#1.

  62. Begone by pommiekiwifruit · · Score: 1

    You PL/1 coder you! Pah, bitstrings...

  63. Apples and Oranges by ChopsMIDI · · Score: 1

    In High School, a buddy of mine wrote on the blackboard:

    1 apple + 2 oranges = 4 orpples

    Yeah, I don't get it either.

    --

    How could I say to men: "Speak louder, shout! For I am deaf!"? -Ludwig van Beethoven
  64. ***Error**** by goneutt · · Score: 0

    divide by banana error
    reload "UNIVERSE"
    RESTART Y/N ?

    --
    Bacardi + slashdot = negative karma.
  65. Can't believe nobody has chosen this one... by embeejay · · Score: 1

    E=mc^2

  66. My favorite by NorwBlue · · Score: 1

    and i'm afraid one that affect most of us (Norwegian Blues: taste is inversely proportional to lust with a factor of sex. But then again it might just be me *sigh*

    1. Re:My favorite by Dwedit · · Score: 0

      Congratulations, welcome to the Division By Zero club.

  67. F=dp/dt by kf6auf · · Score: 1

    Becuase when written like this it holds for relativistic (crotch)rockets. Weeee! (If you look really hard you can even see Hawking.)

  68. Mine, mine ! by sla291 · · Score: 2, Informative

    my stupid one would be : lim( sqrt(8) , 8->9) = 3 :)

  69. Law of Eristic Escalation by Anonymous Coward · · Score: 0

    Imposition of Order = Escalation of Chaos

  70. do derivitives count? by bob · · Score: 1

    d/dx [e^x] = e^x

  71. Will you people never learn! by Skrekkur · · Score: 1

    Fellow nerds dont you know that 1+1=10 ;) Join us now and the help make the internet a better place to live in.ATAOTW (Anti-troll association of the world)

  72. 1+1=2 by Anonymous Coward · · Score: 0

    it's simple and though the basis of all logic.

    cb

  73. ideal gas law by Anonymous Coward · · Score: 0

    PV=nRT

  74. My favourite equation by Pan+T.+Hose · · Score: 0

    Karma = Mensa + Harvard

    But, seriously. My favourite equation is (EURval/USDval)=EURperUSDrate, where EURperUSDrate is the current EUR per USD rate. Why? Because every time I use it, it means that I have some money.

    --
    Sincerely,
    Pan Tarhei Hosé, PhD.
    "Homo sum et cogito ergo odi profanum vulgus et libido."
    1. Re:My favourite equation by Professeur+Shadoko · · Score: 1

      Don't you have a similar equation involving waist circumference and boobies size ?

    2. Re:my favourite equation by Anonymous Coward · · Score: 0
      Taylor's neperian logarithmic of (-1) = (Ramanujan's PI) * i

      (function of real number) = (imaginary part of the complex number)

      open4free ©

  75. Or, if you live in russia... by Anonymous Coward · · Score: 0

    It means the math exercise is done with you! ...seriously, having a 0=0 result for a systems of equations, more often than not means you did something wrong.

  76. A number, not an equation but good nontheless by DongleFondle · · Score: 1

    Working in the realm of web design and art, one of my favorite 'mathematical concepts' has always been the golden ratio. Now, I realize that this is really more a number than it is an equation, but at any rate it is truly amazing to experiment in the world of design with how shapes adhering to the golden ration often bring about more pleasing and content looking designs as well as playing with the inexpressible startling feel of a design with say, one aspect out of touch with the golden ratio whereas everything else adheres.

    1. Re:A number, not an equation but good nontheless by Anonymous Coward · · Score: 0

      Gotta love the power of suggestion. Someone did an experiment on this; the golden ratio is not the most pleasing ratio for a rectangle. The whoe thing is a myth. I recommend you read "The Cult of the Golden Ratio" by Martin Gardner.

    2. Re:A number, not an equation but good nontheless by Aim+Here · · Score: 1

      Well

      Phi - 1 = 1/Phi

      is the equation which nicely shows off where the golden ratio gets all it's pretty properties from.

      Hope this helps.

    3. Re:A number, not an equation but good nontheless by Aim+Here · · Score: 1

      Erm, perhaps I meant

      Phi + 1 = 1/Phi

      Phi, and 1/Phi tend to merge into one number for me, for obvious reasons

  77. Re:Fermat's Last Theorem by Alranor · · Score: 2, Funny

    I once found a remarkable proof of this fact, and wanted to share it with the world, but there was not enough space in the signatures on Slashdot to write it.

  78. Quadratics by Anonymous Coward · · Score: 0

    One I always remember from schooldays.
    General solution for a quadratic equation
    If ax^2 + bx + c = 0
    Then x = -b +/- (b^2 - 4ac)^0.5/2a

    1. Re:Quadratics by shobadobs · · Score: 1

      I always liked to mess with my teachers by using this version:

      x = 2c/(-b +/- (b^2 - 4ac)^0.5)

    2. Re:Quadratics by Anonymous Coward · · Score: 0

      Slight correction to avoid any ambiguity
      x = (-b +/- (b^2 - 4ac)^0.5)/2a

  79. 2 + 2 = 5 by SteelLynx · · Score: 0, Redundant

    Couldn't see it in any of the other comments ;-)

    --
    It's 19:11:42. Do You Know Where Your Meat Body Is?
  80. S = k ln(W) by mu22le · · Score: 1

    S entropy
    k Boltzman constant
    W number of possible microscopic states avaible.

    An equation that ties disorder in the microscopic world (something invisible and fundamental) to such concrete things as temperature and pressure.
    And entropy is probably the most fascinating concept in statistical mechanics.
    I study particle physics but I always tought this is the most elegant equation I've ever seen.

    PS
    According to wikipedia:
    "S = k log(W) is engraved on Boltzmann's tombstone at the Vienna Zentralfriedhof."

  81. This one from string theory by Anonymous Coward · · Score: 1, Interesting

    1+2+3+4+...=-1/12 !!!
    In fact it's not a joke. It's called a zeta function regularization.

  82. The one that proves black is white... by Niffux · · Score: 1
  83. Stoke-Carten Theorem. by paulatz · · Score: 1

    The integral of omega on the frontier of theta is equal to the integral of d-omega on theta. In LaTeX: $\int_{\partial\theta}\omega=\int_{\theta}d\omega$

    --
    this post contain no useful information, no need to mod it down
  84. F = MA by sPaKr · · Score: 1

    Newtionian mechanics, nothing is simpler, more straight forward or less correct. Sure all you hot shot kids with your Relativity or String theory think your cool. Newtonian mechanics, understood and tamed since the greeks, but not written down until Newton. With Newton we get the industrial revolution, had the church been raigned in during Galalio we might have been on the moon hundereds of years eariler. Fewer things can be less obvious yet hit with such impact then Newton.

    1. Re:F = MA by angle_slam · · Score: 1

      My physics professor loved this equation. He said that the reason he was drawn to physics in the first place was because he didn't have to remember anything when he took a test, he just derived it himself using F = MA.

  85. The Slashdot Equation by jolyonr · · Score: 4, Funny

    Of special importance to slashdot:

    garbage in = garbage out
    Jolyon

    --


    Please read my Canon EOS tech blog at http://www.everyothershot.com
    1. Re:The Slashdot Equation by Anonymous Coward · · Score: 0

      My favourite is Bush + White house = Monkey + Coconut.

    2. Re:The Slashdot Equation by tootlemonde · · Score: 1

      This dictum is often applied to decision-making systems with the assumption that it is self-evident. However, there are many systems where it is not true including garbage processing systems.

      All input is influenced by bias (conscious or unconscious), measurement errors, sampling errors, and human frailty.

      As a result, every system should test the validity of its input for consistency and completeness. There are statistical adjustments that can correct non-random data and draw conclusion within bounds of certainty of the accuracy of the input. This process accounts, in part, for why polls and surveys express their results within a margin of error.

      Garbage in, garbage out applies to a garbage can, but for a garbage processing system, the rule is garbage in, composte out. One can consider Slashdot as such a system.

    3. Re:The Slashdot Equation by Piquan · · Score: 1

      garbage in = garbage out

      Ah, but if only 't'were so. For the output of a computer, when given garbage, is indeed itself garbage-- but a muchly different garbage. The output often becomes so refined, and organized, and clarified, that it is often mistaken for Infallible Truth that may not be questioned.

    4. Re:The Slashdot Equation by iggymanz · · Score: 2, Funny

      That's one of the four equations of the Slashdot Unified System.

      The Existence of the Inevitable Dupe:
      yesterday's story == tomorrow's story

      Resonance of the Herd Mentality:
      as opinion(user) approaches opinion(mob), karma of user increases

      The Jakov Smirnov Obverse Transform:
      For any operation U on X which yields Y, in Soviet Russia, operation Y yields X on U!

  86. What about by rkurzawa · · Score: 1

    1/3 = 0.333333...

    2/3 = 0.666666...

    3/3 = 0.999999...

    Yet we are always told that 3/3 = 1

    --
    .nosig
    1. Re:What about by crull · · Score: 3, Insightful

      0.999999... is just another way of symbolising the value 1. Its the same value, just two ways to write it.

      --
      this is not my signature.
    2. Re:what about by mysticwhiskey · · Score: 1

      Oh shit, not only that, but 0 = 1... OMFG!!! Seriously, x=x+1 (or x++ for those such inclined) is a programmatical statement, not an equation to be evaluated.

      --

      Stuck down a hole! In the middle of the night! With an owl!

  87. how about this one by fender_rock · · Score: 1

    my friend and i came up with this one the other day: stress = work / time

    1. Re:how about this one by fender_rock · · Score: 1

      No, it would mean (stress * time)/work = 1

      I think YOU FAIL IT. :) Have a nice day.

  88. One Unknown by mysticwhiskey · · Score: 1

    My favourite is any equation with one unknown - that means I'm one step away from (hopefully) getting something useful!

    --

    Stuck down a hole! In the middle of the night! With an owl!

  89. This is my favorite... by EmagGeek · · Score: 1

    The Integral of e to the x is equal to F times mu times N.

    But seriously...

    One of my favorites is equation 2.36 in my master's thesis (from waaaay back)..

  90. The Pythagorean Theorem by syntap · · Score: 3, Insightful

    I use this in day-to-day life probably more than anything else. Helpful for calculating my home theater projector screen sizes when I need to one-up friedns that get new televisions.

    1. Re:The Pythagorean Theorem by yderf · · Score: 1

      At my university one of the profs there is hooked on this theorem. There are around 400 known proofs to it, and around 60 of them are attributed to the University of North Florida because of Dr. Tong! You gotta love that.

  91. What, no "monkey dance" jokes? by Anonymous Coward · · Score: 0

    The equation that describes the Ballmer series of jumps in the monkey dance is a good example, as are chemical equations that embody observations about reactions seen under his armpits.

  92. binary by fender_rock · · Score: 2, Funny

    Maybe its me, but many people seem to like the number 4. Perhaps its because lots of people are always showing others that they can count to 4 on their fingers in binary.

    1. Re:binary by mysticwhiskey · · Score: 0

      Heh, a four-fingered person who can count to binary on one hand? They're either a cartoon scientist, or an autistic savant from hillbilly country...

      --

      Stuck down a hole! In the middle of the night! With an owl!

    2. Re:binary by mysticwhiskey · · Score: 1

      (Apologies to those who have lost a finger in an accident)

      --

      Stuck down a hole! In the middle of the night! With an owl!

  93. Good old high school humor. by NilObject · · Score: 1

    My favorite is the integral of e to the x equals the functions (the 'f') of u to the n.

    Write it out.

  94. Re:Submitter and Parent are stupid by sgant · · Score: 1

    yes, I just copied and pasted from the article.

    --

    "Leo Fender was in a 'state of grace' when he designed the Stratocaster." -- Paul Reed Smith
  95. well..in that case by themusicgod1 · · Score: 1

    why not f(n) = (phi^n-(1-phi)^n)/(sqrt(5)) ?

    (actually I think I'm thinking of some other equation much like this one, but my math text and notes are in another room in this complex. oh well) [points for anyone who knows what phi and f(n) are in this case]

    --
    GENERATION 26: The first time you see this, copy it into your sig on any forum and add 1 to the generation.
  96. Obligatory Simpson's Reference by CastrTroy · · Score: 1

    1,782^12 + 1841^12 = 1922^12

    --

    Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.
  97. Long equations by WhoReallyCares · · Score: 0

    I've been taught (BTW during my Electronics lectures) that equations longer than 6 cm are completely useless. Please keep this in mind during YOUR Electronics lectures. :-)

  98. 1/3 + 1/3 + 1/3 by Anonymous Coward · · Score: 1, Interesting

    1/3 + 1/3 + 1/3 is interesting too. If expanded to decimal form, .3333.... + .3333.... + .3333.... = .999999....

    where does the last .000....00001 comes from?

    I like to ask people if they know how to add, and when they answer 'of course I do', I ask them to explain that one to me.

    1. Re:1/3 + 1/3 + 1/3 by crull · · Score: 1

      there is no 0.000...00001. the fact that 0.999999... is infinite makes it equal to 1. 0.999... is just another way of describing the value of 1.

      --
      this is not my signature.
    2. Re:1/3 + 1/3 + 1/3 by Tyler+Durden · · Score: 1

      .00000...0001 is a fictitious concept. Basically what you're saying is take an endless expansion of 0s after a decimal point and add a 1 to the end of it. No such animal exists.

      As stated before, 0.99999999... is exactly equal to 1.

      --
      Happy people make bad consumers.
  99. here ... by Anonymous Coward · · Score: 0

    1) goldener schnitt
    http://de.wikipedia.org/wiki/Goldener_Sch nitt
    2) hessische normalform
    http://www.moses.tu-berlin.de/Mathemat ik/LineareAl gebra/Themenseitensourcen/Ebenen/ebenen.html
    3) the one to make the mandelbrot ...

  100. Gaussian by asciimonster · · Score: 1

    f(x) = exp(-(x-mu)^2/(2*sigma^2))/(sigma*sqrt(2*pi))

    No matter how much we try to be individuals, whe allways caught under this bell-shaped curve...

    Whoever said philosophy and formula's don't mix?

  101. quotient rule by gandalphthegreen · · Score: 1

    I especially like the quotient rule, where we have f(x)/g(x): f'(x)=(g(x)f'(x)-f'(x)g'(x))/(g'(x))^2. Or, more easily, if we let f(x) be "Hi" and g(x) be "Ho" and say "D" for derivative, it becomes f'(x)=HoDHi-HiDHo/HoHo

  102. 1=1 by anarxia · · Score: 1
    1=1 makes building SQL strings so much easier.

    sql = "SELECT .. FROM blah WHERE 1=1"

    Then you can add any number of conditions with:

    sql += " AND x=y"

    or you can make it even fancier with:
    sql += " " + operator + " x=y"
    where operator = "AND" or "OR"
    1. Re:1=1 by PingPongBoy · · Score: 1

      Not ever having the training to work with databases, I do this all the time. Is there a better way?

      BTW I do not plan to make database work a lifelong career.

      --
      Know your pads. One time pad: good for cryptography. Two timing pad: where to take your mistress.
  103. Atiyah-Singer by khallow · · Score: 1

    I've been slowly trying to figure out the Atiyah-Singer index formula. See here and here. Does someone know of a good discussion of this formula?

  104. The importance of notation by tootlemonde · · Score: 4, Interesting
    Over at the Historia-Matematica discussion list, the members debated a similar question:

    As you know, notation has helped the progress of mathematics. Consider, for example, the limitations of the Roman number system, the importance of the invention of a symbol for zero, etc.

    Which were, in your opinion, the notations that have permitted the greatest advances in mathematics?

    Apropos to the current discussion was this response:

    the interest of the question:

    > Which were, in your opinion, the notations that have permitted the
    > greatest advances in mathematics?

    (which is very different from any question concerning the history of math. notations) is very close to the interest of the question: who has been the greatest mathematician in the history, e.g. near zero.

  105. and driving the joke into the ground we get .. by Suchetha · · Score: 2, Informative

    you've made an error in your initial assumption, which gives a wrong answer

    First we state that women require time and money:
    Women = Time X Money
    error--^
    this should be
    Women = Time + Money

    and from there onwards ..

    And as we all know "time is money"

    Time = Money

    Therefore by substituting Money for Time we get:

    Women = Money + Money

    Women = 2(Money)

    And because "money is the root of all evil" we therefore can state:

    Money = (Evil)^1/2

    And Since

    2(Money) = Women

    and

    (Money)^1/2 = Evil

    And we are forced to conclude by substituting "women" for "(money)2" from above that:

    Women = 2((Evil)^1/2)

    or in words
    women are double the root of all evil

    which means absolutely nothing

    but hey when you're a maths nazi..

    Suchetha

    --

    learn from yesterday, plan for tomorrow, party tonight
    or one out of three ain't bad
    1. Re:and driving the joke into the ground we get .. by nospmiS+remoH · · Score: 1

      Strictly speaking, time and money does imply "time + money." However, I believe a better way to state it would be to say that the amount of women a man can get is directly proportional to the amount of time and money he has. If he has time and no money, he gets no women. If he has money and no time, he (probably) gets no women. If the equation were time + money, all the bums in the world would get load of chicks because they have nothing but time.

      --
      !hoD
    2. Re:and driving the joke into the ground we get .. by bleckywelcky · · Score: 1

      Awesome! Thank you! I have been struggling with this for a long time. I saw this joke a while ago but couldn't fully appreciate it because it said "time and money" and I always believed that meant addition. However, addition does not fit the equations properly. But as you have so eloquently put it, the amount of women you get is directly proportional to the amount of time you have but is also directly proportional to the amount of money you have. Which fits the equations better AND I believe it characterizes the women-man situation better. Thank you!

    3. Re:and driving the joke into the ground we get .. by Zspdude · · Score: 1
      He's wrong, but the equation still holds. The reason is that a woman actually equates to spending twice as much money as you would usually spend over a given period of time.

      Integrate (2*money dt) to get woman. Or, since time = money just integrate (2*money*dm) to get money^2 + c.



      money^2 + c = woman


      The constant c is always zero, because nothing is constant with a woman ;), leaving

      woman = money^2

      So the formula still holds. Even if you're a math nazi.
      --
      What's in a Sig?
    4. Re:and driving the joke into the ground we get .. by mforbes · · Score: 1

      but hey when you're a maths nazi.

      And coming from a quotes & grammar nazi, I point out that the actual quote is not "Money is the root of all evil," but instead, "The love of money is the root of all evil."

      So therefore, following that same analysis, "Women = Love of 2((Evil)^1/2)"

      --

      Allegedly real newspaper headline from 1998:
      Man Struck by Lightning Faces Battery Charge

    5. Re:and driving the joke into the ground we get .. by Suchetha · · Score: 1

      actually that would make you a bible nazi

      "1 Timothy 6:10 For the love of money is the root of all evils."

      suchetha

      --

      learn from yesterday, plan for tomorrow, party tonight
      or one out of three ain't bad
    6. Re:and driving the joke into the ground we get .. by mforbes · · Score: 1

      Ack, NOooooooo!!!

      Yes, that quote is from Timothy etc, but please-- I'm not bible nazi, bible banger, bible anything. For the most part I consider it a poorly written and poorly documented history of a tribal lifestyle that blended myths from dozens of unattributed sources-- NOT a guideline for living today.

      I'm familiar with large parts of the bible only because I read -a lot-, not because I believe what I read.

      --

      Allegedly real newspaper headline from 1998:
      Man Struck by Lightning Faces Battery Charge

  106. Unidynamics by smellystudent · · Score: 1

    The first law of Unidynamics, formulated by a friend and I during our first year, when we had to move in and out of halls a total of six time:

    Possessions expand to fill 110% of available vehicle space.

    The second law stated that the final 10% would inevitably be found under the bed just when you thought you'd finished.

    --
    Predictive text is shiv!
  107. Some personal favorites by Llywelyn · · Score: 1

    exp( pi*i ) + 1 = 0

    phi^n = F(n) * phi + F(n-1)

    \Delta p \Delta x \ge \frac{h}{4\pi}

    \frac{ \partial^2 f }{ \partial x^2 } + \frac{ \partial^2 f }{ \partial y^2 } + \frac{ \partial^2 f }{ \partial z^2 } = 0

    --
    Integrate Keynote and LaTeX
  108. Re:Submitter and Parent are stupid by sgant · · Score: 3, Interesting

    I submitted it the equation to /. wrong...(thanks for calling me stupid btw, very helpfull)

    But the equation IS e^(i*pi)+1 = 0

    That's Eurler's equation. That's it. You're simply writing it in a different way.

    Hell you can even plug in e^(i*pi)+1 into Google and it will spit out zero. Go ahead, give it a try.

    Also, I won't call you stupid for making this mistake....I'll let it slide.

    --

    "Leo Fender was in a 'state of grace' when he designed the Stratocaster." -- Paul Reed Smith
  109. Shakespeare by Anonymous Coward · · Score: 0

    2B or not 2B == FF

  110. Re:whatthe? by Anonymous Coward · · Score: 0

    In reply to your sig, the human organism is basically an omnivore capable of surviving temporary periods on a vegetarian diet. However, there are sufficient examples of humans suffering allergic reactions to a cereal-based diet for this to be a concern. Animals can be grazed on land unsuitable for growing crops, and are still the best way of creating a textured protein foodstuff.

    If you want to deny your own mortality, fine, but just say "I'm in denial of my own mortality" and don't try to rationalise it or justify it with bullshit.

  111. Fibonacci by demwiz · · Score: 1

    Nothing beats Fibonacci. Useful in many natural aspects of life, and yet so simple. The number is the sum of the two previous in the sequence.

    1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,1 59 7...

    When life is all around and threatening to destroy you, simply go to your happy place and count your numbers.. I got through many public stonings this way.

    --
    -/ demented wizard
  112. Navier-Stokes Equation by utopia27 · · Score: 2, Interesting

    I haven't got the full form handy, but these're the three dimensional equations for motion of fluids.. very elegant, very complete, and spawns a huge mass of special cases.

    As a former Aerospace student, I just had to pitch for good-old N-S :)

  113. kerrching!!! by dark_day · · Score: 0

    sale price - sale cost = profit works for me ;-)

  114. Evaluate the following: by the_twisted_pair · · Score: 1

    B*4*i (U)^0.5 (RU/18)

    ( write it out longhand, replacing the power function with regular symbol... )

  115. My favorite.. by rongage · · Score: 1

    Here's a brain teaser - let's see if YOU can figure it out. And yes, it is correct and provable....

    29 - 1 = 30

    Have fun....:)

    --
    Ron Gage - Westland, MI
    1. Re:My favorite.. by CrosseyedPainless · · Score: 1

      Roman numerals?

  116. E=MC2 by hardburlyboogerman · · Score: 1

    This is easy.
    E=MC2
    Energy=Mornings X 2 cups of coffee
    Works every time :-)

    --
    Geek Hillbilly
  117. Zero by stimey · · Score: 1

    0 + 0 = 0 0 / 0 = 0

  118. a nice formula by Suchetha · · Score: 1

    alphaQ B Cos UR Sec C

    gawds i'm so juvenile..

    suchetha

    --

    learn from yesterday, plan for tomorrow, party tonight
    or one out of three ain't bad
  119. Looks best by jahalme · · Score: 1
    Well, with some iteration, this equation yields the best looking results so it'll be my favourite;

    Z=Z^2+C

    This, of course, is the Mandelbrot set.

  120. 1=2 by ch-chuck · · Score: 1

    Here's the proof:

    1) x = y
    2) x^2 = xy (multiply both sides by x)
    3) x^2 - y^2 = xy - y^2 (subtract y^2 from each side)
    4) (x + y)(x - y) = y(x - y) (factor)
    5) x + y = y (divide out (x - y))
    6) 2y = y (substitute y for x from #1)
    7) 2 = 1 (What do you think of that?!)

    --
    try { do() || do_not(); } catch (JediException err) { yoda(err); }
    1. Re:1=2 by PingPongBoy · · Score: 1

      What kind of proof is that - to start with the assumption x = y for all x and all y? It means you immediately assume 1 = 2, 2 = 8.4, -6.3 = 2.71828, etc.

      --
      Know your pads. One time pad: good for cryptography. Two timing pad: where to take your mistress.
    2. Re:1=2 by ch-chuck · · Score: 1

      There's nothing wrong with 'y=x'. IF x=1 then you know y must = 1 also. If you plot the chart you get a straight line at 45 degree angle. if x=1, y=1; if x=5, y=5; x=-10, y=-10. I can't beleive someone on /. failed elementary 6th grade math.

      Reload and try again - there IS a problem with that proof, but it's not what you guessed.

      --
      try { do() || do_not(); } catch (JediException err) { yoda(err); }
    3. Re:1=2 by Mark+of+THE+CITY · · Score: 1

      It should say "Given: x = y"

      The fault comes in dividing by x-y, which is dividing by 0.

      --
      The clearance system sounds logical. It is not. It is completely arbitrary. -- John Bolton
  121. Girls = Root of evil by Val314 · · Score: 1, Funny

    Thats easy:

    Girls = Time x Money

    Furthermore, we take the statement, "Time is money", and we get:

    Time = Money

    Girls = Money x Money

    Girls = Money^2

    Moreover, the statement, "Money is the root of all evil" means that:

    Evil = the square root of money

    Girls = (Evil)^1/2 (Evil)^1/2

    which reduces to...

    Girls = Evil

  122. MathML ? by peterprior · · Score: 1

    Cookie to the first person who uses MathML" to show their favourite equation :)

  123. Axioms chosen to suit by The+Famous+Brett+Wat · · Score: 1

    In my opinion, the really interesting thing about all this is that you've worked out your axioms from your a priori certainty that 1 + 1 = 2. You chose your axioms to suit that truth, right? I mean to say that any old fool who can add one and one will give you "two" as the answer, but talking about identity operators is a rather more sophisticated concept. It's not like we defined the axioms first, and then figured out that "1 + 1 = 2" follows from the axioms, is it? Seems like cheating, doesn't it?

    --
    proof, n. A demonstration that a conclusion is implied by certain premises and axioms.
  124. bbc had this as well on 8th of october by Anonymous Coward · · Score: 0

    Good old beeb, and no need for registration http://news.bbc.co.uk/1/hi/magazine/3721406.stm

  125. maths=life by mrselfdestrukt · · Score: 1

    Mine is 1+1=3 where the 3rd one is a little small, helpless, stinky meat-popsicle out to ruin your life the bigger it gets. And the 2nd one gets bigger and bigger afterwards, so that it ends up being 1.5 after a while, sometimes even 2 on it's own. The 1st one is left to wither away on it's own so that it actually gets less and less until it just becomes a zero trapped in the daily rat-race of stress,anger and misery trying to support the other two.
    Maybe I'm just bitter...

    --
    "I used to have that really cool,funny sig ,but it got stolen."
    1. Re:maths=life by multipartmixed · · Score: 1

      You know, you should really have that extra testicle removed.

      --

      Do daemons dream of electric sleep()?
  126. This was a poll topic in a past life.

    --
    proof, n. A demonstration that a conclusion is implied by certain premises and axioms.
  127. E = MC2 by Gopal.V · · Score: 1
    My favourite equation ever is

    E = MC^2

    For one simple reason ... It's the simplest equation I've ever seen for such a complicated concept (ie implications on speed of light, absolute time , nuclear bombs and gravity). For simplicity of equation vs the complexity of concept , it wins hands down.

    I've read quite a few books on relativity , still the equation remains the first thing that comes to my mind . Hopefully the grand unified field theory will have such a simple equation behind everything in the world.

  128. While in a gloomy mood... by JamesTRexx · · Score: 1

    2-1=0

    --
    home
    1. Re:While in a gloomy mood... by thhamm · · Score: 1

      hmm. i know it like this:

      "there are three kinds of mathematicians. those who can count, and those who dont."

  129. Ramanujan equation for PI? by AnuradhaRatnaweera · · Score: 1

    How about Ramanujan's equation for PI? It's very simple, but has got some really interesting numbers. A graphical version is available here.

    1/PI = sqrt(8) / 9801 * sum (n = 0 to infinity) (((4n)! [ 1103 + 26390 n ])/ ((n!)^4 * 396^(4n)))

  130. Slashmath by Anonymous Coward · · Score: 0

    1 + 1 = dupe?

  131. Self-love by Oligonicella · · Score: 1

    In one way, being enthralled with any equation is just self-congratulatory. The world around us is the reality, the equations are just forms of communication that we have invented to talk to each other about it.

    1+1=2?? That's just a way to write down on paper what any toddler can show you with two pieces of candy. All else is just higher levels of same.

  132. Euler's formula by Anonymous Coward · · Score: 0

    In school we had a joke going around about Euler's formula and a crackpot professor we have from Kentucky.

    It goes like this:

    In Kentucky Euler's formula is simipified to:

    Ke^ntucky=Kentucky

    Damn he had a confused look when he saw that written on his board.

  133. My personal fave: by Mephie · · Score: 1

    x / 0 = ERROR!!

  134. Gotta be a winner: by tod_miller · · Score: 4, Funny

    us {all,your,base}

    Of course if sets aren't your thing...

    --
    #hostfile 0.0.0.0 primidi.com 0.0.0.0 www.primidi.com 0.0.0.0 radio.weblogs.com
    1. Re:Gotta be a winner: by tod_miller · · Score: 0

      'belongs' symbol 'E' wasn't accepted - imagine it is there... between us and {...

      *sniff*

      --
      #hostfile 0.0.0.0 primidi.com 0.0.0.0 www.primidi.com 0.0.0.0 radio.weblogs.com
    2. Re:Gotta be a winner: by Anonymous Coward · · Score: 0

      Then it would read "us belongs to all your base"? You must be in Soviet Russia?

    3. Re:Gotta be a winner: by Anonymous Coward · · Score: 0

      I always thought it was:

      us {yourbase1, yourbase2, yourbase3..., yourbaseN}

  135. At the moment... generalized Fourier series by dysprosia · · Score: 4, Interesting

    I would have to say, at the moment, my favorite equation would have to be the one giving the coefficients of the generalized Fourier series involving a set of eigenfunctions {p_n}, ie., c_n = <f, p_n>/||p_n||^2.

    Simple stuff, but incredibly cool, considering that Fourier series don't always have to involve just sines and cosines, and you get similar sorts of behaviour.

    1. Re:At the moment... generalized Fourier series by carn1fex · · Score: 1

      Very very interesting to stop and say using the fourier series any function including taking a marker and making a silly line accross a board can be broken down into a sum of good ol sines and cosines. Just when you thought the world was steeped in chaos...

      --

      ---------

      No matter how thin you slice it, its still baloney.

    2. Re:At the moment... generalized Fourier series by Nate+Eldredge · · Score: 1

      But that's true of any orthonormal basis in a Hilbert space. Can't you come up with something deeper?

    3. Re:At the moment... generalized Fourier series by glwtta · · Score: 1
      {p_n}, ie., c_n = /||p_n||^2

      I'm sure I've seen those smileys used on IRC...

      --
      sic transit gloria mundi
    4. Re:At the moment... generalized Fourier series by Anonymous Coward · · Score: 0

      Yah

      do it with wavelets and you will get a Nobel

      oops too late

      This stuff was around before Hilbert, you ass

    5. Re:At the moment... generalized Fourier series by dysprosia · · Score: 1

      I suppose theoretically it's not very deep, but it's a nice result in any case. Even regular Fourier series are rather impressive on some level. I mean a lot of people are enamored by the Euler equation but in essence it's saying that -1 + 1 = 0, which isn't really "deep" at all.

      It all depends on your persepective!

  136. Schrödinger! by k98sven · · Score: 3, Informative

    Come on, folks? The Schrödinger equation!

    H*Psi = E*Psi
    (note: H is an operator folks, not a number)

    Perhaps not as famous as E=mc^2.. or as exact as the Dirac equation (relativistic version of the S.E.),
    but.. in terms of practical benefit to mankind, I think this one has done more than any other equation during the last century.

    Atoms. Molecules. Semiconductors. Lasers.

    The number of things explained and modelled by the Schrödinger equation are just uncountable. You can explain almost* all of chemistry with that thing.

    Relativity is nice, but it hasn't had the technical uses quantum physics has.

    (*Relativistic effects are important in heavy elements. For instance the yellow color of gold is a relativistic effect.)

    1. Re:Schrödinger! by kflash15 · · Score: 1

      Technically, that there is the Time Independent Schrödinger equation... the full equation is

      i*h-bar*deriv(Psi w.r.t. t) = H*Psi

      If we just speak of the time-independent equation we leave out all sorts of quantum mechanical goodness... :-P

    2. Re:Schrödinger! by multipartmixed · · Score: 1

      > H*Psi = E*Psi

      I could've sworn that equation had a Devil's fork in it somewhere.

      Incidentally, I'll buy you a glass of whatever alcohol beverage you'd like, assuming you can solve it for all of the molecules in that beverage.

      --

      Do daemons dream of electric sleep()?
    3. Re:Schrödinger! by k98sven · · Score: 1

      >I could've sworn that equation had a Devil's fork in it somewhere.

      Psi = fork-shaped

      >Incidentally, I'll buy you a glass of whatever alcohol beverage you'd like, assuming you can solve it for all of the molecules in that beverage.

      How about this: I'll solve it for about 100 atoms (which is about as many as can be done with todays computing power) and then use group theory to extrapolate that result to the rest?

      Of course, a co-worker of mine actually did that last year already, using density-functional methods. (which is a reformulation of the Schrödinger equation)

      See:
      Molecular Structure of Alcohol-Water Mixtures
      Phys. Rev. Lett. 91, 157401 (2003)
      J.-H. Guo, Y. Luo, A. Augustsson, S. Kashtanov, J.-E. Rubensson, D. K. Shuh, H. Ågren and J. Nordgren

  137. Mildly amusing identity by Aim+Here · · Score: 1

    I quite like

    (1+2+3+4+5+....+n)^2 = (1^3+2^3+3^3+4^3+...+n^3)

    It seems to come straight out of nowhere - it's not easy to see WHY it's like that (easy to prove though), and the generalisation to other powers is a messy thing involving Bernouilli numbers.

    But under normal circumstances, euler's formula with the e's and the Pis and the square roots of minus one would get my vote.

  138. The fixed point function - Y by arethuza · · Score: 1
    See this. Its lovely - especially when represented in its directed graph form.

    Or in SKI combinator form:

    Y = S (K (S I I)) (S (S (K S) K) (K (S I I)))

    Or possibly even in SK form:

    Y = S (K (S (S K K)(S K K) )) (S (S (K S) K) (K (S (S K K)(S K K) )))

    1. Re:The fixed point function - Y by arethuza · · Score: 1
      Oops

      I know its a function and not an equation.

      I guess the equational form would be:

      Y(X) = Y(Y(X))

  139. my favourite being... by Anonymous Coward · · Score: 0

    2 + 2 = Thomas Jefferson

    It's that new math.

  140. The axioms of set theory by Anonymous Coward · · Score: 1, Interesting

    The answer is simple. The most beautiful equations, hands down, are those from which all of mathematics can be derived. These are the axioms of ZFC set theory. What could possibly be more beautiful or more important than that? And it's a shame so few people know about them. See Zermelo-Fraenkel Axioms and Metamath Proof Explorer.

    1. Re:The axioms of set theory by Anonymous Coward · · Score: 0

      IANAM but if I recall correctly Gödels Theorem implies also that there cannot be a single set of axioms that would define _ALL_ of mathematics.

    2. Re:The axioms of set theory by ortholattice · · Score: 1

      You are right, I should have said "the axioms of ZFC set theory are generally held to encompass essentially all of mathematics".

    3. Re:The axioms of set theory by clarkie.mg · · Score: 1

      But are axioms equations ? Or some axioms are equations ?

      --
      Men are born ignorant, not stupid; they are made stupid by education. Bertrand Russel
    4. Re:The axioms of set theory by zx75 · · Score: 1

      In that case, I believe it consists of :
      {} = 0
      {{}} = 1

      As pure mathematicians like to claim, all of mathematics is derived from the empty set.

      (Note, above {} is the empty set, and {{}} is the set containing the empty set)

      --
      This is not a sig.
    5. Re:The axioms of set theory by ortholattice · · Score: 2, Interesting
      But are axioms equations ? Or some axioms are equations ?

      Well, strictly speaking the axioms are represented as well-formed formulas (wffs) that aren't displayed in the form of equations on the pages I linked to. But using what is called "class notation" in set theory it is always possible to rewrite a wff with an equivalent expression that has form of an equation. For example: "P(x) imples Q(x)" can be expressed as "{x:P(x)} union {x:Q(x)} = {x:Q(x)}" where "{x:P(x)}" means "the class of sets x such that P(x) is true". Or more generally, any statement P(x) that is true of all sets x (such as any of the axioms) can be rewritten "{x:P(x)} = V" where V stands for {x:x=x} i.e. the universe of all sets. Class notation is an extremely powerful device. Classes need not exist as sets, by the way; the class V above is not a set but is called a "proper class". Does this answer your question?

    6. Re:The axioms of set theory by ortholattice · · Score: 1

      In that case, I believe it consists of :
      {} = 0
      {{}} = 1

      As pure mathematicians like to claim, all of mathematics is derived from the empty set.

      That is cute. However you can't get very far with these two axioms. You need some more axioms that will let you build more complex structures starting from the empty set, such as combining them to form pairs, unions, powersets, and so on. You also need to postulate the existence of an infinite set. A quick overview of some of the history behind the axioms, and why they are needed, is given on the Russell paradox page.

    7. Re:The axioms of set theory by zx75 · · Score: 1

      One side-note and a point of interest as expressed by a former professor of mine, was that in mathematics if a true paradox can be formulated, ie. a statement that is both true and false, then the rules/axioms that were used to formulate it are too powerful.

      Like A = set of all sets that do not contain themselves. A is a paradox, because the unresolvable question is, does A contain itself? It does, and it does not.

      Yes, you do need some additional concepts in order to make the null set axioms work, but they are contained within the common rules of set theory.

      --
      This is not a sig.
    8. Re:The axioms of set theory by Anonymous Coward · · Score: 0

      Technically this statement is false: there are concepts in mathematics that cannot be expressed in terms of the Zermelo-Fraenkel axioms for set theory. One of the simplest examples is the proper class of von Neumann ordinals, which in particular is not a set-sized object. True, you can admit large cardinals to allow for larger and larger objects, but these have the appearance of "hacks" on the basic structure. The theory of toposes is probably a better candidate for a foundation of modern mathematics, given that in particular set theory can be modeled by an elementary topos (as shown by Lawvere and Tierney back in the 60s). Toposes can also model things that are much bigger than sets (and arguably more interesting than sets). Lots of people seem to believe that set theory is the only possible foundation for mathematics, and this is a myth that needs to be stomped out of existence.

    9. Re:The axioms of set theory by Anonymous Coward · · Score: 0

      One side-note and a point of interest as expressed by a former professor of mine, was that in mathematics if a true paradox can be formulated, ie. a statement that is both true and false, then the rules/axioms that were used to formulate it are too powerful

      So, apparently, multiplication is too powerful for ZF. That's what Godel used to build the incompleteness theorem, after all.

    10. Re:The axioms of set theory by ortholattice · · Score: 1

      As I mentioned in another post above, I was mistaken not to qualify my statement as "essentially all of mathematics" instead of the rhetorical "all of mathematics" (which I in my haste to post I figured would be simpler for nonmathematicians to understand, but in retrospect it was a judgmental error).

      But you are mistaken about the power of the ZF language. Please read the bottom half of page xiv (14 of 192) in the Preface of the "Metamath" book. This will explain how ZFC, with the addition of just one more axiom to result in Tarski-Grothendieck set theory, can do category theory. That this axiom isn't typically included with ZF has nothing to do with it being a hack - it is actually quite beautiful - but has more to do with tradition and the historical definition of what axioms ZF set theory happens to include. Mathematically there's nothing to prevent having the additional axiom all the time as part of the "standard" axiom set, and the mizar.org project does just this. From what I can tell there is nothing that Tarski-Grothendieck set theory can't do that category theory can do.

      On the other hand no one, to my knowledge, has come up with a foundational set of category theory axioms that are anywhere near as convenient to work with as ZF-type axioms. In fact even finding them explicitly, precisely, and plainly displayed as a simple axiom system to plonk on top of first-order logic is something I have never seen. (I have seen a couple of systems claimed as such, but they were riddled with problems such as ambiguous rules and implicit definitions that weren't made clear if you actually wanted to start working with them mechanically.) So if category theorists want to have a myth "stomped out of existence" they'll have to do better in terms of making it simply accessible in the same way ZF-type axioms are.

  141. The purest of equations by goobie123 · · Score: 1

    This simple formula changed the world when Einstein proved it's truth.

    t=$

    Where:
    t=time
    $=money

  142. 2+2=5 WMDs by tverbeek · · Score: 1

    At least that's what they seem to be teaching in U.S. schools.

    --
    http://alternatives.rzero.com/
  143. Laplace Transform by thebdj · · Score: 1

    While you basically never use the equation and mostly just look stuff up in tables, any Electrical Engineer or anyone else doing differential equations has to love this one:

    Y(s)=integral(exp(-st)*y(t)*d(t),0,infinity).

    I remember this making a great many problems in my EE classes easier. Second is the fourier transform, mostly because its Discrete form makes my Digital signals class so much easier. Guess I have a thing for some hard to type equations.

    --
    "Some days you just can't get rid of a bomb."
  144. 1+1=3, don't take anything for granted. by pbjones · · Score: 1

    believe nothing...test everything.

    --
    There was an unknown error in the submission.
  145. The axioms of set theory by ortholattice · · Score: 4, Informative

    The answer is simple. The most beautiful equations, hands down, are those from which all of mathematics can be derived. These are the axioms of ZFC set theory. What could possibly be more beautiful or more important than that? And it's a shame so few people know about them. See Zermelo-Fraenkel Axioms and Metamath Proof Explorer.

  146. Rendering Equation by palm3D · · Score: 1

    Why hasn't anyone mentioned the Rendering Equation yet?
    I'd type it right here, but it's not really ascii compliant. And it's too damn complicated if you want to get it right.
    Oh well, forget it. Euler's ain't too bad... :-)

    1. Re:Rendering Equation by Goodbyte · · Score: 1

      I prefer the hemisphere formulation: L(x \rightarrow \Theta) + \Int_{\Omega_x} f_r(x, \Xi \rightarrow \Theta)L(x \leftarrow \Xi) cos(N_x, \Xi) dw_\Xi

  147. My favorite by valentyn · · Score: 1

    a^2 - a^2 = a^2 - a^2 :=:
    a ( a - a ) = (a + a) * (a - a) :=:
    a = a + a

    substitute 1 for a: 1 = 2.

    --
    my other sig is a 500 page novel
  148. My Fave by Anonymous Coward · · Score: 0

    ET/k9 = kPAx the famous Western synergy system.

  149. here we go by fishbot · · Score: 1

    0+1 = 1+1 = 1*1 = 1/1 = 1

    Other than that, Euler's jobby, or anything involving j (I'm an electronics engineer, so i is current - and no cracks about 'i am current' either!)

    1. Re:here we go by fishbot · · Score: 1

      arf, I just noticed that I put '1+1' :)

      1+1 is approximately equal to 1 for all practical purposes. There, that fixed it..

      /slinks away

  150. How about this one.... by wpiman · · Score: 0

    I see this equation on alot of bumper stickers where I live..... Marriage = 1 man + 1 woman Certainly not the most elegant- but is does seem to be popular.............

  151. The Laplace Transform by The+Hobo · · Score: 1

    To denote in Maple notation,

    F(s) = int(exp(-s*t)*f(t),x=0..infinity);

    Although not officially an equation, more of an operator, the Laplace transform is extremely useful in my program of study (computer engineering) and it makes complex problems much simpler to solve.

    --
    There is another kind of evil which we must fear most, and that is the indifference of good men. -- Boondock Saints
  152. Comment removed by account_deleted · · Score: 4, Interesting

    Comment removed based on user account deletion

  153. my favorite by glyph42 · · Score: 1

    Okay, another take on it.

    We know that
    1) Time = Money

    It is also well known that
    2) Knowledge = Power

    And most of you will know that
    3) Power = Work / Time

    Substituting 1 and 2 into 3, we get
    4) Knowledge = Work / Money

    Rearranging 4, we get the inevitable conclusion
    5) Money = Work / Knowledge

    Therefore, the more you do, and the less you know, the more money you make. Damn, I should never have gotten this stupid Masters degree!

    --
    Music speeds up when you yawn, but does not change pitch.
  154. Personally.. by Planetes · · Score: 1

    I'd go with Reynolds Transport Theorem or possibly Bernoulli's equation. A whole lot of the modern world wouldn't exist without mathematical representations of fluids.

    --
    Planetes
    "One World, One Web, One Program" - Microsoft Promo Ad
    "Ein Volk, Ein Reich, Ein Fuhrer" - Adolf Hitl
  155. favourite .... by ghum · · Score: 1

    2+2=5

    often used in discussion about synergies.

  156. what about by themusicgod1 · · Score: 2, Interesting

    x=x+1 ? or does that count as two.

    --
    GENERATION 26: The first time you see this, copy it into your sig on any forum and add 1 to the generation.
  157. Windowlicker by fmwap · · Score: 1

    DeltaMi-1=aSigman=1Di(n)(SigmajEC(i)Fij(n-1)+Fexti (n-1))

    Ever seen the face in this song ?
    http://www.eeggs.com/items/34824.html

  158. S=4Pi r^2 by Anonymous Coward · · Score: 0

    This phenomenon can be expressed with expression. This is not special effects but the actually conducted experiment.

  159. Most useful college equation by Anonymous Coward · · Score: 0

    Most useful equation in college: alcohol + girl = sex.

  160. Re:A political one :) by carnivore302 · · Score: 1

    I'm pro-Bush but I think you didn't deserve to get modded as troll. I'm still laughing now..

    This is obviously a plot to show that republicans don't have a sense of humor. I bet you got modded down by a democrat :-)

    --
    Please login to access my lawn
  161. Favorite ... by rbowen · · Score: 1

    lim 5->4 sqrt(5) = 2

    --
    Apache guy, Open Source enthusiast, runner
  162. trial and error. by nounderscores · · Score: 2, Funny

    That's only true for horse shoes, hand grenades and 1950s chemotherapy.

  163. or j by jimbo3123 · · Score: 1

    sqrt(-1) == j

    You can't just start throwing around meaningful things like i. You insensitive clod.

    exp(j theta) = cos(theta) + j sin(theta)

    --
    There should be a moderation category "Dumbest Comment EVER"
    1. Re:or j by Anonymous Coward · · Score: 0

      Amen, my EE brotha!

    2. Re:or j by Anonymous Coward · · Score: 0

      Now shut up and go back in the unemployment line, fool!

  164. In the words of a professional logician "Bull...." by N+Monkey · · Score: 1, Funny

    "All men are mortal
    Socrates is a man
    Therefore, all men are Socrates."


    "The last scene was interesting from the point of view of a professional logician because it contained a number of logical fallacies -- that is, invalid propositional constructions and syllogistic forms -- of the type so often committed by my wife."... :-)

    Monty Python

  165. Imaginary? by Anonymous Coward · · Score: 0

    i^2=-1

    or Sqt(-1)=i

    oe for all the EEs out there

    j^2=-1

  166. First Pythagorean Identity by bindster · · Score: 1

    cos(theta)^2 + sin(theta)^2 = 1 That one's just fun to derive, imo.

    --
    WARNING: DO NOT LET DR. MARIO TOUCH YOUR GENITALS. HE IS NOT A REAL DOCTOR.
  167. Requisite Achewood reference by Plutor · · Score: 1

    " Congratulations, a^2 = b - 1, you are the Equation of the Week!"

    (There was a tshirt available, but it's been discontinued as of just last week. Sorry)

  168. convergence by Anonymous Coward · · Score: 0

    I think my favorite of all time is the integral of 1/x from 0 to infinity, which diverges, and the integral of the rotation of 1/x, which is the integral of pi*(1/x)^2 which converges to pi. I always found that to be kinda cool

  169. Hamiltonian operator by dpilot · · Score: 1

    I really like the reference to Hamilton inside the wave equation. Back in the early 1800s Sir William Rowan Hamilton was working with ways to express optics and dynamics with a single equation framework. At the time, the effects were mainly felt in optics, but it presaged quantum mechanics.

    --
    The living have better things to do than to continue hating the dead.
  170. Something most of you will not never understand ;) by JollyFinn · · Score: 1

    1+1=9
    The point is this: he who sows sparingly will also reap sparingly, and he who sows bountifully will also reap bountifully.

    I'm expecting that slashdotters don't get how those two things are connected.
    For some have might have seen this in version 1+1=3 but I think the text explains why thats my favourite equation in that form ;)

    --
    Emacs is good operating system, but it has one flaw: Its text editor could be better.
  171. My personal favorite by antifoidulus · · Score: 1

    E=MC Hawking!

  172. one of the more famous misquotes there by devphil · · Score: 1


    And because "money is the root of all evil" we therefore can state:

    A classic misquote. The verse actually runs, "The love of money is the root of all evil," but this joke wouldn't be as funny that way.

    Still, people's "serious" attacks on various Christian attitudes towards money usually hinge on the misquote. Just some trivia to brighten your day.

    --
    You cannot apply a technological solution to a sociological problem. (Edwards' Law)
    1. Re:one of the more famous misquotes there by Zak3056 · · Score: 3, Insightful

      A classic misquote. The verse actually runs, "The love of money is the root of all evil," but this joke wouldn't be as funny that way.

      It's still funny--you just have to change the punchline to "The love of money is the root of all women."

      --
      What part of "shall not be infringed" is so hard to understand?
    2. Re:one of the more famous misquotes there by Uzziel · · Score: 2, Interesting
      The first place I encountered that quote was in Chaucer's Canterbury Tales, and it wasn't given in English, but in Latin:
      Radix malorum cupiditas est.
      You could translate "cupiditas" as "the love of money", but it's more accurate to just call it "selfishness".
    3. Re:one of the more famous misquotes there by SammyTheSnake · · Score: 1

      Funny, I found it in the bible

    4. Re:one of the more famous misquotes there by Tevye · · Score: 1

      I've also seen on a woodcut plaque,

      "Lack of money is the root of all evil."

      --
      We're on a mission from God.
    5. Re:one of the more famous misquotes there by jhurshman · · Score: 1

      The word in the original Greek seems to be a much more specific term (meaning "love of money") than the Latin "cupiditas". Also, the context of the saying makes it clear that "money" is in view.

      --

      Do not speak unless you can improve on the silence.
    6. Re:one of the more famous misquotes there by Uzziel · · Score: 1
      You're absolutely right; it does show up in Timothy first. But according the the Vulgate Bible, the word used is still "cupiditas":
      radix enim omnium malorum est cupiditas quam quidam appetentes erraverunt a fide et inseruerunt se doloribus multis
    7. Re:one of the more famous misquotes there by Thuktun · · Score: 1

      It's still funny--you just have to change the punchline to "The love of money is the root of all women."

      Not derivable from those equations, but perhaps just as insightful, "The love of women is the root of all money."

    8. Re:one of the more famous misquotes there by SammyTheSnake · · Score: 1

      Just for the sake of completeness, I looked up what it is in greek (the language Paul wrote - or more correctly dictated- it in) and the answer is:

      Unfortunately, my greek isn't fantastic so I did some more poking around, and AFAICS the magic word is or "philarguria" which I can only find translated as "love of money".
      Indeed, "phil" means "love of" (philosophy, love of thinking; philanthropy, love of mankind; philophax, made up word) "arguria" means "silver" (the chemical symbol of silver is "Ag")

      I've completely forgotten what my point was, if I ever had one, but I had so much fun rooting this out, I don't honestly care! :)

      Have a nice day, all

      Cheers & God bless
      Sam "SammyTheSnake" Penny

  173. New Kind of \. Poll by JDonahoe · · Score: 1

    So have \. polls evolved? Rather than voting, we're skipping straight to bitching about choices.

  174. Having fun with math by RenHoek · · Score: 1

    My best liked equasion:

    2 + 2 = 5 (for large values of 2)

  175. girls = evil by MagicMerlin · · Score: 0, Redundant

    how about the proof that girls are evil?

    Merlin

  176. My fav... by Eric_Cartman_South_P · · Score: 1
    BitTorrent Link = Free TV + Software - adverts - activation

    *ducks*

  177. Oops Typo! by PenguiN42 · · Score: 1

    Rewrite x+1=S(x) as x+S(0)=S(x).
    Substitue x = S(0), S(0)=S(0)=S(S(0))

    What am I missing?


    That should have been S(0)+S(0)=S(S(0))

    --
    The following sentence is true. The preceding sentence was false.
  178. Profit = Revenue - Expenses by CrazyTalk · · Score: 0

    Sorry, had an accounting midterm last week...

    1. Re:Profit = Revenue - Expenses by Anonymous Coward · · Score: 0

      Wrong. Net Income = Revenues - Expenses

      When profits are discussed we usually mean gross profits, which is Sales - Cost of Goods Sold.

      Assets = Liabilities + Owner's Equity + (Revenue - Expenses) + (Gains - Losses)

      Revenue, Expense, Gain, and Loss all fold into Owner's Equity. Their net effect is 'comprehensive income', which is what you might be terming 'profit'.

    2. Re:Profit = Revenue - Expenses by CrazyTalk · · Score: 1

      You are, of course correct - but I was just giving a simplified version. And don't forget dividends, which are not included in Retained Earnings!

  179. Mathematician's Limerick by Have+Blue · · Score: 1

    Integral of z^3 over (1, 3^(1/3)) *cos(4*pi/9) = log(e^1/3))

    Integral z cubed dz From 1 to the cube root of 3 Times the cosine Of four pi over nine Equals log of the cube root of e!

    (I may have gotten this wrong, as the two terms are only identical to three decimal places on my calculator.)

    1. Re:Mathematician's Limerick by Have+Blue · · Score: 1

      (Now let's try it with line breaks...)

      Integral of z^3 over (1, 3^(1/3)) *cos(4*pi/9) = log(e^1/3))

      Integral z cubed dz
      From 1 to the cube root of 3
      Times the cosine
      Of four pi over nine
      Equals log of the cube root of e!

      (I may have gotten this wrong, as the two terms are only identical to three decimal places on my calculator.)

    2. Re:Mathematician's Limerick by pclminion · · Score: 1
      The log of the cube root of e is just 1/3.

      I guess it doesn't rhyme as well that way, though :-P

  180. Theorem of Pythagoras by amightywind · · Score: 2

    Without a doubt the most important equation of all time is the theorem of Pythagoras:

    a^2 + b^2 = c^2

    It is found virtually everywhere in mathematics and physics: from grade school geometry, trigonometry, calculus, non-Euclidian geometry..., to the Tanyama Shimura Conjecture.

    --
    an ill wind that blows no good
    1. Re:Theorem of Pythagoras by fgb · · Score: 1

      but it's only a special case of the law of cosines:

      a^2 + b^2 = c^2 - 2*a*b*cos(theta)

      cos(90) = 0

  181. Girls are evil by darksith69 · · Score: 0, Redundant

    Not mine, I saw this on http://pasky.ji.cz/

    First we state that girls require money and time:
    girls = money * time
    As we all know, 'time is money':
    time = money
    Therefore:
    girls = money^2
    And because 'money is the root of all evil':
    money = sqrt(evil)
    Therefore:
    girls = sqrt(evil)^2
    And we are forced to conclude that:
    girls = evil

  182. Joke Time by TrentL · · Score: 5, Funny

    George Bush still doesn't know if Bin Laden is alive! After numerous rounds of "We don't even know if Osama is still alive", Osama himself decided to send George Bush a message in his own handwriting to let him know that he was still in the game.
    Bush opened the letter and it appeared to contain a coded message:

    370HSSV-0773H

    Bush was baffled, so he typed it out and e-mailed it to Colin Powell. Colin and his aides had no clue either so they sent it to the CIA. No one could solve it, so it went to the NSA and then to MIT and NASA and the Secret Service.

    Eventually they asked Britain's M I6 for help. They cabled the White House: "Tell the President he is looking at the message upside down."

  183. Buffon's Needles by Anonymous Coward · · Score: 0

    Buffon's Needles has always amazed me. It is a theory that finds the value of pi.
    pi = 2*n/c
    Just get a table with parallel lines on it drawn one inch appart, and get lots of needles one inch long. Lay down the needles randomly. (Diagonally, too)
    n = number of needles layed down
    c = number of times a needle crosses a line.

  184. Lest we forget the Normal equation by Cauchy · · Score: 1

    f(x) = \frac{1} {\sqrt{2 \pi \sigma^2}}
    e^{\frac{{x-\mu}^2}{\sigma^2}}

  185. Simpler equations by Hawke · · Score: 1
    X+0=X

    X*1=X

    X^1=X

    Without these, algebra comes significantly harder.

  186. My favorite is by code+prole · · Score: 1

    Kime = FV @ impact.

    It's a martial arts thing. Kime, or focus, equals force times velocity at impact. I.E. The harder you hit them the harder they fall.

    -- No .sig for you! NEXT!

    --
    -- coding for the proletariat since 1977
  187. master theorem by sporty · · Score: 1

    How can you deny the goodness of the master theorem?

    --

    -
    ping -f 255.255.255.255 # if only

  188. Fractals and Iteration by Anonymous Coward · · Score: 1, Interesting

    Fractals of course can be produced from many different equations, but the iterative process of many simple equations produces amazing fractals:

    x=x^2+1 where the "=" should be a two way arrow.

    P.S. is there a keyboard encoding for a two way arrow? How about in UTF-8?

  189. No question by HangingChad · · Score: 1
    PV = nRT because I had the hands down best looking gal on campus for a chemistry lab partner. She'd wear these short little running shorts and half-tops...amazing I learned anything at all. And she had the brains to rival the looks.

    To this day if I get a whiff of that perfume she used to wear I can't help thinking about mass balance equations.

    Those were great days.

    --
    That's our life, the big wheel of shit. - The Fat Man, Blue Tango Salvage
  190. 2 + 2 = 5 by Anonymous Coward · · Score: 0

    'nuff said.

  191. Come together by Anonymous Coward · · Score: 0

    1 + 1 + 1 = 3
    Got to be good looking cause he's too hard to see.

  192. THE equation by Anonymous Coward · · Score: 0

    Quite a few here have suggested that elegance could be sought in the geometric realm. a^2 + b^2 = c^2 is quite interesting, very useful for many things.

    However, one equation does stand out. In 1637, a Frenchman who had mathematics as a hobby made a seemingly innocent note in the margin of one of his surprisingly few math books (Arithmetica):

    "It is impossible to split a cubus into a sum of two cubi, a 4th power into a sum of two numbers in the 4th power, and in general any power greater than 2 into a sum of two powers equal to the first, for which I have found a truly wonderful proof. This narrow margin, however, cannot contain it."

    Sounds interesting? Unfortunately, when he died in 1665, the proof was never found. A proof, but unlikely the same, was announced in 1993, and published in 1995.

    Pierre de Fermat was the name. Mathematicians like Euler and Cauchy failed to prove this. This was the problem that sparked my interest in mathematics, not only because of the statements simplicity, but also the history of the problem. Blood, sweat and tears, indeed!

  193. Here is one... by MadEmperor · · Score: 1

    1.99999 = 2

  194. pythagorean theorum! by Leroy_Brown242 · · Score: 1

    A^2 + B^2 = C^2 By far, my favorite.

  195. Maxwell Equations by legrimpeur · · Score: 1

    Maxwell Equations! They just work! They were formulated before relativity theory was out, yet they proved relativity invariant. As soon as you write them for real media instead for the void they work a little worse, though...

  196. PV = nRT by lobsterGun · · Score: 1

    don't ask me why. I always liked that one.

    1. Re:PV = nRT by berbo · · Score: 1

      Because you're an idealist?

    2. Re:PV = nRT by Anonymous Coward · · Score: 0

      Measured P, V, and n for a gas of marbles. Yes, marbles. Looked up R (7/2), was shocked to find T in the tens of millions.

  197. The boys' club strikes again by Anonymous Coward · · Score: 0

    And people wonder why women are discouraged from pursuing math and science.

    1. Re:The boys' club strikes again by Anonymous Coward · · Score: 0

      If a joke discourages you from pursuing the subjects you love, then I say good riddens to bad rubbish.

    2. Re:The boys' club strikes again by Anonymous Coward · · Score: 0

      It's not an isolated thing. There's a lot of misogyny floating around these fields, and a lot of pressure to just go along with it.

      But of course preserving the jokes is more important. And if the object of the jokes feels unwelcome, well, good riddance to bad rubbish.

      For a subculture that prides itself on being meritocratic, geekdom (in the Slashdot sense) is awfully rooted in privilege.

  198. Getting the Ideal Gas Law Right by radtea · · Score: 2, Interesting

    I was amused to see the ideal gas law amongst the contenders, written as PV = nRT where n is in some weird units and R is some weird constant.

    A much nicer form is:

    P = nkT

    where n is the number density of particles and k is Boltzmann's constant.

    For some reason chemists persist in using 12 divided by the mass of the proton in grams as the basis for all measurement, and this choice leads to a proliferation of strange constants and units. I know there are historical reasons for this, but one only has to look at the way physics has re-invented its notation and concepts repeatedly over the years to realize that historical reasons are no excuse.

    Written in a sensible form, the idea gas law is a very beautiful equation, though not so beautiful as the Dirac equation, which is the only differential equation in physics that I'm aware of that describes reality and only reality.

    All the other equations we use have non-physical as well as physical solutions, and we quietly throw out the non-physical solutions. We sometimes even try to maintain that mathematics is "unreasonably successful" as a means of describing reality, when we know perfectly well that half of what our equations describe has no physical counter-part, but is just an ugly artefact of an imperfect description.

    --
    Blasphemy is a human right. Blasphemophobia kills.
    1. Re:Getting the Ideal Gas Law Right by karups2 · · Score: 1
      "Written in a sensible form, the idea gas law is a very beautiful equation..."

      This must be related to the "Dopeler effect", for high density of dopes.

      (The Dopeler effect refers to the tendency of stupid ideas to seem smarter when they come at you rapidly.)

  199. pi = 16*atan(1/5) - 4*atan(1/239) by mosschops · · Score: 1

    My personal favourite, as found in "Pi and the Arithmetic Geometric Mean" by JM Borwein and PB Borwein, Wiley, 1987.

  200. The basis of asymmetric keys by Gelfman · · Score: 2, Interesting

    Surely a serious contender for most elegant equation must be M = PQ and the associated factoring problem when given M and the knowledge that {P, Q} are prime and P Q. This is without doubt one of the simplest bit of maths to explain to anyone. It is also almost as old as multiplication itself and fundementally uncracked by modern number theory. A number theory problem that is expressed by 4 symbols and can be explained to a child of 10 that has confounded mathemeticians for centuries and continues to do so. How elegant and wonderfully fiendish is that?

    --
    ...and, on the seventh day, God switched off his Mac.
  201. Slightly old news... by wongn · · Score: 2, Informative

    This news story was in The Times about a month ago... I can recall it interviweing some of the people that voted for 1 + 1 = 2 as the best equation. Euler's was probably the best of them. In itself it seems to show the beauty and... strangeness of math in that three entirely irrational numbers that you'd feel have no link whatsoever can be so intristically linked.

  202. Lennon and God by Anonymous Coward · · Score: 0

    My favorite equation is from the Beatle's song "Come Together": 1+1+1=3

    John Lennon's formulation of the Christian Trinity.

  203. Law of the iterated logarithm by r6144 · · Score: 1
    Look here.

    The theorem is: let {a_n} be a series of independent and identically distributed random variables with variance sigma^2, S_n be its partial sum (in other words, S_n=a_1+a_2+...+a_n), then

    lim sup_{n->infinity} abs(S_n)/(sigma*sqrt(2*n*log(log(n))))=1, almost surely.

    To put it more plainly, suppose you do a random walk, starting from origin, and every second you goes one step right or left with equal probability and independent from your earlier steps. Intuitively, as time goes by, you will reach places farther and farther from the origin. Indeed, after n seconds and for very large n, according to the central limit algorithm (which is taught in most elementary probability classes) your position will almost follow the Gaussian distribution with a standard deviation of sqrt(n) steps. In other words, after n seconds, you will have about 5% chance to be more than 1.96*sqrt(n) steps from the origin, a 0.1% chance to be more than 3.29*sqrt(n) steps from the origin, etc. However, it is always possible that you be as far as 10*sqrt(n) or 100*sqrt(n) from the origin (of course no farther than n steps), though the probability is very small. This theorem in a sense puts a limit on this variation of your distance from the origin. It basically means that almost every time you do such a random walk ("almost surely" means "with probability one", so it can fail to happen in principle but not in real life), you are going to get farther than sqrt(n), or 10*sqrt(n), 100*sqrt(n), etc., at some (possible very large) time n; indeed you will get as far as sqrt(1.999*log(log(n)))*sqrt(n) for infinitely many times; however, if you happen to get as far as sqrt(2.001*log(log(n)))*sqrt(n), take care to record that splendid event, for it will happen only for a finite number of times, after which you will never get this far (relative to n) during this random walk! Sounds a little complex, but simpler propositions such as "you will never get farther than 5*sqrt(n) before time n" are obviously wrong.

    It is fascinating because stuff like log(log(x)) does not occur very often in fundamental mathematics (except maybe in the complexity analysis of algorithms), but it occurs here as a very strong and important result concerning a problem often met in everyday life.

  204. Didnt see this one by revco_38 · · Score: 0

    Slashdot + link = server meltdown

  205. Big Brother is Watching or For Unusually Large 2's by Digitus1337 · · Score: 0

    2 + 2 = 5

  206. Mine (with someone else) by ghereheade · · Score: 1

    Integral from 10 to 13 of 2*X dx.

    You'll have to prove you're a real nerd and solve that one.

  207. fractals, chaos theory and Lorenz by Anonymous Coward · · Score: 0

    lorenz, founder of chaostheory, he made a simple model to describe the climate of earth, where the whole weather system is described with 3 variables, so this is NOT to predict the weather

    dx/dt = s (y - x),
    dy/dt = r x - y - x z,
    dz/dt = x y - b z,

    where x,y,z are variables
    and s,r,b are constant parameters

    i would give more fractal equations, but lorenz remains my favourite

  208. navier-stokes by SCHecklerX · · Score: 1

    Mainly because using them is somewhat an art form.

    1. Re:navier-stokes by mysterious_mark · · Score: 1

      I concur most heartily, Navier Stokes is one of the Milenium problems, see: http://www.efunda.com/formulae/smc_fluids/navier_s tokes.cfm for a brief overview. MM

  209. Re:correction !=n by jellomizer · · Score: 0

    I Think your browser Sucks. I would suguest that you stop using IE. In Mozilla I get e^(i) + 1 = 0 and (the Greek Simbol of Pi) != n although they look simular in the small font

    --
    If something is so important that you feel the need to post it on the internet... It probably isn't that important.
  210. My favourite by skaife · · Score: 1

    Power = VI

  211. circumference by Ian_Bailey · · Score: 1

    twinkly twinkle little star
    circumference equals 2 pi 'r'.

    I'm a sucker for rhymes.

  212. Pi:O = 4:[] by Anonymous Coward · · Score: 0

    or A = Pi*r^2

    I've known this equation for over twenty years and yet I still find new meanings and uses.

  213. My favorite: 2=1 by cecil36 · · Score: 1

    Proof right here: http://www.math.toronto.edu/mathnet/falseProofs/fi rst1eq2.html

    Of course everyone here knows that I divided by 0.

  214. Women = Evil by static0verdrive · · Score: 4, Funny

    Here's my favorite:

    First we state that women require time and money:
    Women = Time x Money

    And as we all know "time is money"
    Time = Money

    Therefore by substituting Money for Time we get:
    Women = Money x Money
    Women = (Money)^2


    And because "money is the root of all evil" we therefore can state:
    Money = (Evil)^1/2
    And Since
    (Money)^2 = Women
    Then (Money)^2 = Evil

    And we are forced to conclude by substituting "women" for "(money)^2" from above that:
    Women = Evil

    Can't argue with mathematical proof!

    --
    ========
    77 77 77 2e 6d 65 6c 76 69 6e 73 2e 63 6f 6d
    1. Re:Women = Evil by rpillala · · Score: 2, Interesting

      It's such an old joke and I'm such a math teacher that I'm forced to point out that:

      let x = -3then x^2 = 9
      if you take the square root of both sides you get x = 3.

      Technically you should instead write |x| = 3 which covers the actuality that x is in fact -3. I had to find a way to explain the + or - part of the quadratic formula to my Algebra 2's and that's what I did.

      What you've really proved is that women are either evil or the opposite of evil.

      --
      When the axe came to the forest, the trees said, "Look out - the handle was once one of us."
    2. Re:Women = Evil by Chrispy1000000+the+2 · · Score: 1

      Ahh, but you forgot the Fun Factor.

      Oh, yeah, this is slashdot, I forgot...

      --
      Sig
    3. Re:Women = Evil by Anonymous Coward · · Score: 0

      women are either evil or the opposite of evil.

      It really does seem that way. Especially since you often don't know which a woman will be at any given time.

    4. Re:Women = Evil by Anonymous Coward · · Score: 0

      Oops. "and" is the sum operator, not the multiplication operator.

    5. Re:Women = Evil by akincisor · · Score: 1

      No No!
      Either women are evil, or they are negative and evil!

    6. Re:Women = Evil by geekoid · · Score: 1

      for the love of god, it's:
      "the love of money is the root of all evil"

      --
      The Kruger Dunning explains most post on /. http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
    7. Re:Women = Evil by Anonymous Coward · · Score: 0

      I have heard that a better translation is "The love of money is a root of all kinds of evil".

  215. And I screwed up by jbolden · · Score: 1

    And to further prove my point I actually screwed up. You have to have a more complex multiplication for this to be a field at all. The counter example still workse since any vector added to itself is 0 but not all vectors are invertable in my original.

  216. B4i4Q (RU/18) QT(Pi) by objekt · · Score: 1

    nm

    --
    -- Boycott Shell
    1. Re:B4i4Q (RU/18) QT(Pi) by Anonymous Coward · · Score: 0

      That's not an equation, it's an expression.

      An equation has two expressions separated by an equal sign.

  217. All time best.... by Trumpetgod2k1 · · Score: 0

    (you - clothes / legs) * (me - clothes)

  218. You can include pi in that as well... by newt · · Score: 1

    The Jargon File quotes that one as "pi = 3, for small values of pi and large values of 3."

    (particularly unfunny in FORTRAN, where you could redefine the value of integers by saying things like "LET 1 = 4". Try debugging the code that comes after THAT!

    - mark

    --

    -----
    I tried an internal modem, but it hurt when I walked.

  219. One of my favorites by miskatonic+alumnus · · Score: 1

    is \int_{\-infty}^{\infty}e^{-x^2}dx = \sqrt{\pi} with the associated quotation from Lord Kelvin:

    A mathematician is one to whom that is as obvious as that twice two makes four is to you. Liouville was a mathematician.

  220. test by Anonymous Coward · · Score: 0

    test

  221. I'm partial to by jzarling · · Score: 2, Funny

    1 Bourbon + 1 Shot + 1 Beer = :)

    --
    It is better to be the hammer than the anvil.
  222. Zeta function by yderf · · Score: 1

    How about: Re[Zetafunction] = 1/2.

    Prove it and get a million dollars!

    I has all sorts of links to the gamma function (factorials), and primes. Good stuff galore.

  223. Due to Lomont and Brillhart by pjt33 · · Score: 1
    Proving this was the highlight of my symbolic summation dissertation. Markup in LaTeX:
    \begin{displaymath} \sum_{j = 0}^{s} \frac {(-1)^{j} (m + n - 2j) {m \choose j} {m - j
    \choose m - s} {n \choose j} {n - j \choose n - s} {m + n \choose j} {m + n - s - j -
    1 \choose s - j}} {{s \choose j}^{2}} = 0 \end{displaymath}

    For the benefit of those who can't read TeX, that's

    SUM from j = 0 to s of (-1^j (m + n - 2j) mCj (m - j)C(m - s) nCj (n - j)C(n - s) (m + n)Cj (m + n - s - j - 1)C(s - j)) / (sCj^2) = 0
    where
    aCb = a! / (b! (a - b)!)
    is a binomial coefficient.
  224. 1+1=? by Anonymous Coward · · Score: 1, Insightful

    As a computer scientist, I quickly learned:
    1+1=2 (already knew that)
    1+1=1 (boolean)
    1+1=10 (binary)
    1+1=11 (unary)

  225. You're all nerds.... by Anonymous Coward · · Score: 0

    Come on? My favorite equation? Wha?

  226. It May have been said before by sydres · · Score: 1

    2+2=4, you know the Reference

  227. what about drake's equation by ptr2004 · · Score: 1
    N = R* × fp × ne × fl × fi × fc × L

    http://open-encyclopedia.com/Drake_equation that estimates alien civilizations

  228. Best eq. ever by Anonymous Coward · · Score: 0


    / x n
    |e = f(u)
    /

  229. Kerry + Edwards = USA - Bush by bushwahd · · Score: 1

    Need I say more?

  230. 4=3 by Garabito · · Score: 1

    If a + b = c

    then

    (4a-3a)+(4b-3b) = (4c-3c)

    4a + 4b -4c = 3a + 3b -3c

    4(a+b-c) = 3 (a+b-c)

    4 = 3

    More here

    1. Re:4=3 by Anonymous Coward · · Score: 0

      Division by zero "fomulae" are lame.

  231. measuring power of gas boiler by ajs318 · · Score: 1

    To measure the power of a gas boiler, knowing the flow rate V litres per minute and the inlet and outlet temperatures, just multiply the temperature difference by the flow rate by 0.07.

    Q = m * c * theta ..... (1)

    In one minute (=60"), we have V litres of water flowing, or about V kg. So dm/dt = V/60 kg s-1. c is about 4168 J kg-1 K-1. But it'll be easier to handle power in kilowatts, so we shall divide everything by 1000.

    Power = flow rate [LPM] / 60 * 4.168 * temp diff [C]
    = flow rate [LPM] * temp diff [C] * 4.168 / 60
    = (about) flow rate * temp diff * 0.07

    That's as close as you're likely to get it anyway due to system inaccuracies.

    --
    Je fume. Tu fumes. Nous fûmes!
    1. Re:measuring power of gas boiler by pclminion · · Score: 1
      The reason this works is because the temperature is an excellent approximation of the pressure for incompressible fluids (when multiplied by the appropriate constant). What you're really computing is the product of flow rate times pressure difference.

      This is a very interesting analog between electricity and fluid flow. For electric flows, the power is the voltage times the current. For fluid flows, the power is the pressure difference times the flow in liters per second.

      This is easily shown by some simple dimensional analysis:

      Volt * Amp = Joule / Coulomb * Coloumb / Sec = Joule / Sec = Watt
      Newton / Meter^2 * Meter^3 / Second = Newton * Meter / Second = Joule / Sec = Watt

      In other words, "Volts" are the equivalent of "Pressure" in the fluid world, and "Amps" are the equivalent of flow rate.

  232. the best is by Anonymous Coward · · Score: 0

    6 x 9 = 42 It sums up all life. IE You never get what you expect from life.

  233. Re: who did first invent PI? by Anonymous Coward · · Score: 0
    Shortly ...

    ln(-1) = PI * i
    sqrt(-1) = 1 * i
    ...

    PI = (Taylor's eulerian logarithm of -1) * -i
    PI = (Euler's taylorian logarithm of -1) * -i
    PI = Ramanujan's equation

    Who did first invent the equation of the longest real of PI?

    open4free ©

  234. 1+1=10 by toph42 · · Score: 1

    Obviously...

  235. s*e^x = F(u^n) by mencik · · Score: 1

    Originally seen as integral of e^x = F(u^n), but tough to make integral sign without special characters.

    1. Re:s*e^x = F(u^n) by Anonymous Coward · · Score: 0

      Eh, needless change of variables (and n?! what are we? CS people doing calculus? Oh wait...) Really ought to just remain e^x+c.

  236. A^2+B^2=C^2 by Shotgun · · Score: 3, Insightful

    A^2+B^2=C^2

    This is the only equation that will give you the quickest way from here to there in an airplane.

    --
    Aah, change is good. -- Rafiki
    Yeah, but it ain't easy. -- Simba
    1. Re:A^2+B^2=C^2 by balaam's+ass · · Score: 1

      This is the only equation that will give you the quickest way from here to there in an airplane.

      Not on a curved earth. (Not for anything but short distances, anyway.)

    2. Re:A^2+B^2=C^2 by rnelsonee · · Score: 1

      But if you're using Cartesian map cordinates (longitude, latitude) to figre out A and B on a globe, this is incorrect. When you view the shortest path from A to B on a flat Cartesian map, it becomes curved (for example, flying from LA to Tokyo takes you over Alaska at one point). Google "Great Circle Route", unless you already knew all this.

    3. Re:A^2+B^2=C^2 by srleffler · · Score: 1

      I don't think latitude and longitude are a Cartesian coordinate system. I agree with you otherwise, though.

    4. Re:A^2+B^2=C^2 by Brian_Confucius · · Score: 1

      The cartesian coordinate system is used for flat surfaces, yep. It was in vented by Rene Descartes (1596-1650). Mapping the globe with longitude and latitude was Gerhardus Mercator's (1620-1687) idea.

  237. Moles by flatface · · Score: 1
    Shame on you, Slashdot. Right after International Mole Day, too.

    Avagadro's number: N=6.02*10^23

  238. Re:Something most of you will not never understand by CrosseyedPainless · · Score: 1

    Hey, that's really deep. Maybe you should get together with this guy.

  239. Not that great equation by Gadzinka · · Score: 1

    It isn't that great an equation.

    I distinctly remember reading somewhere, that there is nothing special about the equation

    e^{i\pi} = -1 % (TeX notation)

    It's just the consequence of the way that exponentiation on complex numbers is defined.

    Sorry, can't find the link to it now.

    Robert

    --
    Bastard Operator From 193.219.28.162
    1. Re:Not that great equation by pclminion · · Score: 1
      It's just the consequence of the way that exponentiation on complex numbers is defined.

      Yep. The series expansion of exp(i*x) turns out to be the same as the series expansion of cos(x)+i*sin(x). Thus, exp(i*x) = cos(x)+i*sin(x).

      It's hardly surprising that pi would enter into it, given the presence of the trigonometric functions.

      However, there's still something a bit mysterious about the fact that the two series are identical to each other. But it's probably no more meaningful than finding a particular pattern of tea leaves on the bottom of your cup...

    2. Re:Not that great equation by roystgnr · · Score: 1

      It's just the consequence of the way that exponentiation on complex numbers is defined.

      Exponentiation on complex numbers is defined to be the analytic extension of exponentiation on real numbers. The power series definition looks arbitrary, but it isn't - any different definition of complex exponentiation either wouldn't be differentiable everywhere or wouldn't be the same as real exponentiation.

  240. 1 + 1 = 10 by ultrajazz · · Score: 0

    1 + 1 = 10

  241. S*e(x)=f(u^n) by PhilipDC78 · · Score: 1

    The function of multiplying s times the exponentional of x is equal to a function of u to the nth power. This is the greatest equation of all. S*e(x)=f(u^n)

  242. Another form by Rick+Genter · · Score: 1

    Though it was mentioned in the article lead-in, I prefer the form

    e**(pi)i = -1

    to the form

    e**(pi)i + 1 = 0.

    --
    Don't underestimate the power of The Source
  243. Mine is the... by Anonymous Coward · · Score: 0

    Drake Equation : N = R* fp ne fl fi fc L

  244. T=F by Anonymous Coward · · Score: 0
    "1=0", or in its other instantiations, since from it you can deduce _anything_...;)

    --
    Try Nuggets , the mobile search engine. We answer your questions via SMS, across the UK.

  245. -1 = 1 ? by ojek · · Score: 1

    -1 = i^2 = i * i = sqrt(-1) * sqrt(-1) = sqrt(-1 * -1) = sqrt(1) = 1

    My discrete math teacher in uni got us scratching our heads for a while before he explained what was wrong with that "equation".

  246. My favorite is E=MC2 by MrJerryNormandinSir · · Score: 0, Redundant

    E=MC2

  247. Taylor Series approximation by Anonymous Coward · · Score: 0

    is the most important equation...

    1. Re:Taylor Series approximation by Anonymous Coward · · Score: 0

      Absolutely. We never could have calculated anything important.

  248. My Favorite describes something I never understood by charleste · · Score: 1

    After 7 years in college getting fancy degrees in Math and Physics, there's still something I don't get: Thermodynamics. So my Favorite is my Nemesis: PV=nRT. I can only thank God I took statistical thermo instead of physical thermo, or that blessed C wouldn't have allowed me to postpone being a grown up for a few more years in grad school :-)

  249. Bayes Theorem by EvilNight · · Score: 1

    I've always been intrigued by Bayes Theorem myself.

    For those who's eyes glass over while reading the explanations in that wiki link, you may find this intuitive explanation of Bayes Theorem (complete with Java applets) a bit easier to wrap your mind around. As for why folks think it's important... it's the basis for the Scientific Method. It's also a candidate for one of the fundamental principles of AI: the ability to draw conclusions intelligently. Be careful, reading about this could suck up half of your day. Of course, if you wanted to be productive, you probably wouldn't be reading Slashdot in the first place.

    --
    Hell is being intelligent in a world full of idiots.
    1. Re:Bayes Theorem by pclminion · · Score: 1
      That's intuitive?!

      Bayes' Theorem is so obvious it hurts:

      1. P(A,B) = P(A|B) * P(B) (obvious)
      2. P(A,B) = P(B|A) * P(A) (obvious)
      3. P(A|B) * P(B) = P(B|A) * P(A)
      4. P(A|B) = P(B|A) * P(A) / P(B)
      QED

  250. (eq? #F '()) by j.leidner · · Score: 1
    False is not NIL, you insensitive clod!

    --
    Try Nuggets , the SMS search engine with question answering technology.

  251. Knowledge = Work / Money by balaam's+ass · · Score: 1

    Grad skul joke:

    Knowlege = Power

    Power = Work / Time

    Time = Money

    Therefore,

    Knowledge = Work / Money

    (The more you work, the more you know. And if you want to know alot, you go to grad skul, where you hardly get paid...)

  252. 1 1 2 3 5 8 13 ... by Soldrinero · · Score: 1

    F(n) = F(n-1) + F(n-2). This has got to be up there. This series is supposed to show up practically everywhere in nature.

    --
    I would rather be killed by a terrorist than enslaved by my government.
  253. Two that should be defined by erykjj · · Score: 1

    0/0 = 1
    1/infinity = 0

    1. Re:Two that should be defined by Anonymous Coward · · Score: 0

      While the latter is obvious and by no means undefined, the former is not necessarily true, or defined for that matter.

  254. Re:correction !=n by Sexy+Commando · · Score: 1

    What makes you think IE doesn't display Pi correctly? Next time you might as well say Pi does not display correctly on Mozilla compiled by Microsoft/RIAA/MPAA/SCO/RFID/DRM/LOL/LMAO.

  255. Best equasion by pchasco · · Score: 1

    a^2 + b^2 = c^2

  256. Am i the only one... by Cigarra · · Score: 1

    ...who actually sees a Pi in the original posting formula?

    --
    I don't have a sig.
    1. Re:Am i the only one... by Carnildo · · Score: 1

      Am i the only one who actually sees a Pi in the original posting formula?

      Not quite.

      --
      "They redundantly repeated themselves over and over again incessantly without end ad infinitum" -- ibid.
  257. Mmmmm! by ekvin · · Score: 0

    mmmm, P=IE!

  258. The ones in my 6th grade math notebook. by Gldm · · Score: 1

    I remember being 11 and since I was in the "advanced" math group, we were being taught the beginnings of algebra. Basic stuff like exponents and solving x + 7 = 5 solve for x, etc. I noticed an interesting shortcut for figuring out the square of a number. I could always just get the square of the previous number and add two, and it was always an odd number. So, not knowing all the symbols and stuff I wrote down an explanation of this somewhat like "If you have x^2, then all you have to do is start with 1, and for every square bigger the difference is you add two." A little while after this I was graphing Y=X and noticed that the row and columns that intersected it were always one larger each time Y=X grew by one. I knew the area of the square covered by it was related, and when I worked out the numbers I figured out how it related to what I was talking about earlier, and then wrote that down too.

    My teacher, when I showed this too her just went "that's nice, but you shouldn't use shortcuts for things like squaring numbers because shortcuts don't always work and you might get it wrong and then if you can't show your work you get no credit." My parents did something similar. Even when I used the same things for a "math project" we were made to do in 9th grade or so a few years later, I got alot of "Well it's interesting but so what?" even though by then I'd found a way to expand it to more than squares. The way I did was after alot of agonizing time with a calculator trying to figure out the shortcut for cubes, I figured out that all you have to do to make a bigger cube is take the existing cube, throw a square of depth 1 on each side, throw 3 lines of length one an depth 1 inbetween those squares, and then throw an extra 1x1x1 in the corner. Doing it with a 4D version (which I didn't know the name for at the time but I'd assume it's a tesseract) I guessed would involve adding some cubes, some squares, some lines, and the 1 block again. After a bunch of work with a pocket calculator doing trial and error I figured out it was 4 cubes, 6 squares, and 4 lines. And from there I figured out a way to get the answers for higher numbers in the X^N series.

    But nobody ever really cared when I showed it to them.

    10 years later, I was forced to retake calculus 2 in college after my school decided my AP credit now only counted for calc 1 instead of 1 and 2 because they'd switched from 3 credit to 4 credit classes. Since I barely remembered my precalc stuff I had my mother ship out all my math notebooks (which is easy when you've been colorcoding your notes by subject all through HS) so I'd at least have all my old cheatsheets.

    When I got the oldest yellow book in the stack, I flipped through it and found the pages where I'd first written this stuff. I reread it and then it suddenly made alot more sense when I knew what symbols you'd really use to express that idea. They were:

    X^2 dy/dx = 2x+1
    and
    (integral)2x = X^2

    and the expanded form from later?
    x^3 = 3x^2 + 3x + 1
    x^4 = 4x^3 + 6x^2 + 4x + 1

    and from there figuring out if you lined them up in a row and added the two numbers on either side from the row above you go the next row, like this:

    1
    1 2 1
    1 3 3 1
    1 4 6 4 1
    1 5 10 10 5 1
    1 6 15 20 15 6 1

    etc.

    These days of course, nobody ever believes me when I tell them I figured all this stuff out between the ages of 11 and 14.

    To this day I still hate math, and can't do algebraic long division because I use my own shortcuts for doing it with actual numbers, much to the dismay of my statistics professor who was amazed I could divide 5 numbers into 9 in my head in less than 10 minutes but not simplest algebraic equations into another even with writing it out and all the time in the world.

    --

    Introducing the new Occam Fusion! Now with sqrt(-1) fewer blades!

  259. equation... by Anonymous Coward · · Score: 0

    Pythagoran Theorem
    a^2+b^2=c^2

  260. Greatest evar? by NeoSkandranon · · Score: 1

    I'm fond of Euler's equation, but in my line of study (Computer engineering) However Ohm's law I see nearly every day in some form or other (Lab work or Network theory classes)

    --
    If you can't see the value in jet powered ants you should turn in your nerd card. - Dunbal (464142)
  261. Exp[ i*Cir/2] + 1 = 0 by cryptochrome · · Score: 2, Interesting

    Richard Feynman once famously remarked that Euler's Identity was the most remarkable equation in mathematics, since it combined all the really important numbers into one formula. Recently while attempting to formulate a technically-oriented conlang, I was considering what numbers really were important and concluded that there was one number of massive significance that was left out, and another was formulated somewhat arbitrarily.

    Firstly, 2 is a very important number. 0 is null and the origin, 1 is unity - but 2 is the purest expression of difference and distinction. Dualism is everywhere: 0-1, On-Off, Up-Down, Left-Right, In-Out, Real-Imaginary. Everything has its opposite. Many concepts can only be considered in the context of two objects or states. 2 is the base of the humble but indispensible bit - and consequently the base of the logarithm that yields the number of bits necessary to express a number or code. 2 is indispensible.

    Secondly, Pi was chosen somewhat haphazardly. For the unit circle of radius 1, Cir = 2*Pi. Pi is the ratio of a circle's circumference to it's diameter. But from a mathematical standpoint the diameter is not what's important - the radius is. Wouldn't it make just as much sense if not more to use the ratio of the Circumference to the radius (here designated as Cir)? The way things are formulated now, Pi is half a cycle in radians, halfway around the unit circle. Wouldn't a constant that represents a full cycle, Cir, make more sense? Have we grown so used to Pi that we have forgotten the arbitrariness of it's formulation?

    Of course if you choose to use Cir, 2 naturally works its way into Euler's equation as well.

    Exp[i*Cir/2]+1=0

    Mathematicians, please respond.

    --

    ---If you can't trust a nerd, who can you trust?

    1. Re:Exp[ i*Cir/2] + 1 = 0 by pomakis · · Score: 1
      IANAMBIHAMOMDSTSC (I Am Not A Mathemetician, But I Have A Master Of Mathematics Degree, So That Sorta Counts).

      Doesn't the very fact that using Cir instead of Pi complicates the equation give you a tip-off that Pi is the more fundamental unit?

      And yeah, I agree that 2 is a fundamentally important number as well, but it can be derived from the concepts of 1 and addition, buth of which are already represented in Euler's equation.

    2. Re:Exp[ i*Cir/2] + 1 = 0 by cryptochrome · · Score: 1

      The appeal of Euler's identity is not just that it is simple, but that it includes all the "important" numbers. Thus you have to decide what's important first before you can even consider whether the equation is simple/elegant/meaningful.

      Anyway, 1 plus 1 depends on what Field you are computing in. Specifically, in the smallest field 1+1=0; although this field has only two elements, 0 and 1. Of course lots of things are left out of this system, but it does have its uses.

      --

      ---If you can't trust a nerd, who can you trust?

    3. Re:Exp[ i*Cir/2] + 1 = 0 by Gil-galad55 · · Score: 1
      Actually, if you wrote it as exp(i*Cir) - 1 = 0, you wouldn't have to introduce 2. I don't find the addition of 2 to be very compelling. The duality you discussed can be more simply described with just 1 and 0 -- you don't need to count the elements, really. Compare this to a sphere; if you consider the SPACE the sphere is in, you need three dimensions, whereas if you consider only the sphere, you just need two. That is why GR is treated with manifolds now rather than an extension of traditional diff. geometry, which would require five (!) dimensions. That thought makes me sad.

      In any case, though, I'm very down with using Cir instead of pi, but I don't think it would fly.

      --

      To follow knowledge like a sinking star, / Beyond the utmost bound of human thought. ("Ulysses", Tennyson)

    4. Re:Exp[ i*Cir/2] + 1 = 0 by bodrell · · Score: 1
      Secondly, Pi was chosen somewhat haphazardly. For the unit circle of radius 1, Cir = 2*Pi. Pi is the ratio of a circle's circumference to it's diameter. But from a mathematical standpoint the diameter is not what's important - the radius is. Wouldn't it make just as much sense if not more to use the ratio of the Circumference to the radius (here designated as Cir)? The way things are formulated now, Pi is half a cycle in radians, halfway around the unit circle. Wouldn't a constant that represents a full cycle, Cir, make more sense? Have we grown so used to Pi that we have forgotten the arbitrariness of it's formulation?
      I think you're a little mixed up. Pi is not arbitrary. And you just defined pi in terms of circumference and diameter, but why not in terms of area and radius? Area = pi * r^2, which is pretty elegant. If pi were the ratio of circumference to radius, then it would be 2 pi ~ 6.28. Then the aread of a circle would be pi * r^2 / 2.

      Regardless, pi shows up in a lot more places than circles and sines. You can multiply it by a constant, but it will still be irrational, and will still show up in all the same equations--multiplied by an arbitrary constant.

      As of now--the sum of the interior angles of a triangle = 180 deg. = pi radians. Would you prefer Cir/2 radians?

      --
      Si la vida me da palo, yo la voy a soportar Si la vida me da palo, yo la voy a espabilar
    5. Re:Exp[ i*Cir/2] + 1 = 0 by auf_weiderzen · · Score: 1

      I think that the important thing is the distinction that pi is a *ratio*. Cir is a defined quantity, because you can have a Cir of 4, 5, 6.28..., etc. and it is a valid variable, but not a fixed constant. Pi, on the other hand, is the fixed constant associated with the variable dimensional descriptors (radius/diameter and circumference) and defines their interrelationship.

      Okay, so I'm kinda talking out of my ass and using big words to cover it up, but I think it makes sense. (Maybe I should've been a philosophy major...)

      --
      Lusers, lusers, everywhere and not a LART in sight.
    6. Re:Exp[ i*Cir/2] + 1 = 0 by j-beda · · Score: 1

      Pi has survived in mathematics as Pi rather than being subsumed in a new Cir=2*Pi because Pi appears in so many more places than 2Pi does. I sumbit without any proof that if 2Pi was more useful than Pi, that is what we would be using. This is a bit related to the Planck's constant "h". "h" was efined by Planck for one particular calculation, and it was found to be useful in lots of other places, and to be a fundamental parameter of the univers. However "h" tends to appear in many uses along with an extra factor of 1/2Pi (as an aside, this would be an example where "Cir" might be more "useful" than Pi - if they were more common we might be thinking of Cir as the fundamental unit and Pi as being half of that). Since h/2Pi appears so often, people started to use a new symbol to represent that quantity (drawn as an "h" with a line through it, called "hbar"), and in many situations "hbar" is the preferred constant. Had Planck defined "hbar" instead of "h", we probably would not even talk about "h" at all, but only occasionally use the quantity 2(Pi)(hbar) when it was needed.

  262. Rounding the edges by opus18 · · Score: 1

    0! = 1 Not for its beauty, but for it's craftsmanship.

  263. Great....now I have some 'splainin to do by mdp1173 · · Score: 1
    Office worker: Excuse me, why are you turning your head as if to look at your screen upside down?

    Me: Nevermind

    1. Re:Great....now I have some 'splainin to do by RevAaron · · Score: 1

      Haha... I came upon your post right when I was righting myself after doing the very same thing. eh eh eh. Luckily I have an office all to myself...

      --

      Working toward a usable PDA environment in the spirit of Newton OS: Dynapad
  264. My Favorite Equation by jtaylor72 · · Score: 1

    The Angleof the Dangle is Inversely Proportional to the Heat of the Meat.

    --Beavis and Butthead

  265. ru/18 comes to mind by Anonymous Coward · · Score: 0

    followed by SQRT(69)

  266. Classic Electormagnetics Roxors? by Anonymous Coward · · Score: 0

    Maxwell's equations cannot be topped, IMO. Not only do they look cool, but I hear you can actually calculate stuff with them. Maybe.

  267. God by kenp2002 · · Score: 1

    N+1=N

    --
    -=[ Who Is John Galt? ]=-
  268. Another nice EE mnemonic by tvar · · Score: 1

    ELI the ICE man!

    Remembering that EMF is just another name for voltage:

    V = L * ( dI / dt)

    I = C * ( dV / dt)

  269. what we use at Improv... by Dr.+Molf · · Score: 1

    COMEDY = TRAGEDY - PANTS

    --
    indeed..
  270. infinity by Anonymous Coward · · Score: 0

    .999... = 1

    that just messes with my head.

  271. Fourier Integral Theorem by warrior · · Score: 1

    I don't have the charset to write it up here, but those of you that are familiar with it no that there is no bound (no pun intended) to it's utility. Here's a link to the equations on MathWorld.The extensions of this theorem, the Laplace integral and Z-transform are equally important. These equations enable us to project functions of time onto periodic functions which we can then use to analyze the frequency content of the original function. They also enable us to easily solve differential equations and discrete difference equations.

    Mike

    --
    Intel transfer the difficult from Hadware to software, for get more power, programmer need more technology. -- chinaitn
  272. Zero divided by zero??? by Anonymous Coward · · Score: 0

    Isn't it amazing that:

    for any value of n,
    n * 0 = 0

    yet n / 0 = either infinity or is undefined

  273. The most important eqation by clem9796 · · Score: 1

    that I ever learned in college:

    R(yE)^12=Pi(EyD)

    --
    IANALOOA
  274. 1 = 2 (with proof) by asynchronous13 · · Score: 1

    My favorite has got to be 1 = 2. Here's the proof.

    x = x

    x^2 = x^2

    x^2 - x^2 = x^2 - x^2

    x*(x-x) = (x+x)*(x-x)

    x = x+x

    x = 2x

    1 = 2

    1. Re:1 = 2 (with proof) by jesseraf · · Score: 1


      Division by zero...thank you come again.

  275. 2^(aleph-zero) = c by arjay-tea · · Score: 1

    Ie: 2 raised to the power of the number of integers,
    equals the number of real numbers. I think this
    can be credited to George Cantor.

  276. siebheil? by rjshields · · Score: 1

    What does that mean? :)

    --
    In this world nothing is certain but death, taxes and flawed car analogies.
    1. Re:siebheil? by Flashbck · · Score: 1

      I think he meant 71346315 which translates to siegheil....

      Damn Nazi

  277. Ar there no Owellians? by X-Nc · · Score: 1
    2+2=5

    Doubleplusgood.

    --
    --
    If I actually could spell I'd have spelled it right in the first place.
  278. The YUM Equation by Anonymous Coward · · Score: 0

    1 + 1 = 69

    Beats anything you geeks can come up with and I doubt that most of you can solve it ;-).

  279. Favorite Equation... by Anonymous Coward · · Score: 0

    That's not an 'n', but a pi symbol. Anyway, my favorite equation is: t1=t0(sqr(1/(v/c))), known as a Lorentz Transformation Equation.

  280. I prefer confusing people with by Tired_Blood · · Score: 1

    2 + 2 = 11

    all in radix-3, of course.

    Since you mentioned ThinkGeek, the concept is more in lines with this one.

    --
    This is not my sig.
  281. Only for small v by nameer · · Score: 1

    It's a truncated taylor series expansion. At home I have a copy of the paper that Einstein published. Anyway, here is the first link that poped up on Google showing this. The point is, if v is a significant fraction of c, then you cannot neglect the higher order terms.

    --
    "Uh... yeah, Brain, but where are we going to find rubber pants our size?" --Pinky
  282. secret of the universe by Anonymous Coward · · Score: 0

    7129 / 6105195

  283. My fav: by Anonymous Coward · · Score: 0

    So just that you know, my fav:

    2 x 2 sometimes= 5

    Not as solid as 1 + 1 = 2, but nothing compares to the beauty of unknown, unpredictable and breaking rules.

    Eventually everything we know for certain, becomes boring, no matter how exciting it might have been initially.

    Just a Random.Idea.

  284. simple by 97cobra · · Score: 0

    42

  285. LatTex? Ascii? by berbo · · Score: 1

    How come we still can't render these beautiful, important equations in XHTML?

  286. RDRR? by Wandering+Wombat · · Score: 1

    Har dee har har!

    --
    I like to place meaningful quotes in my sig, so people will know that I know what meaningful quotes are.
  287. Chef Equation by flackrum · · Score: 1

    You + me... + her too, simultaneous
    You + me... + your momma + your sister =
    Simultaneous lovin' baby, * two or three...

  288. Most relevant algorithmic equation by Highpriest · · Score: 0

    P ? NP It was even floating around in that episode of the Simspons where homer goes into the dimensional warp, lol.

  289. Re:My Favorite describes something I never underst by bleckywelcky · · Score: 1

    This one is easy because it describes static thermodynamics (ie a system that isn't continually changing).

    So, here we go. Let's assume we have a little ball filled with a gas. The ball has a volume V. The gas inside the ball is at a pressure P. The number of moles of gas we have pumped into the ball is n. The temperature at which the gas inside of the ball is at is T. And scientists before us have determined that all of these parameters are related to each other through a constant, R. So, we know all of this information: we know the V of the ball, we know the P of the gas, we have put in n moles of gas, we know the constant R, and we know the T of the gas.

    Now, the equation states PV=nRT is always true for this little 'system' (our ball). So, let's change one of the parameters and see how it affects the other parameters. Let's heat the ball up to raise the T a known certain amount. So, we place the ball in the oven and let it heat up a tad. Now, what has changed? Well, let's assume that the heat does not deform the ball at all, so V doesn't change. We have not put in or let out any moles of gas, so n doesn't change. R never changes (it's a constant). And we have changed T ourselves, so that means that P must change.

    So, using the same V, n, and R values as before, plug in the new T temperature value (after heating) and solve for our new P pressure value. This is what the pressure will be after we heat the ball to our new T temperature.

    This is the most basic example of how to use this equation. As well, this equation is called the "Ideal or Perfect Gas Law" and assumes all gasses act in a ideal or perfect manner. In reality, gasses don't act exactly ideal or perfect and the ideal gas law needs modification to accurately predict the behavior of real gasses. However, this is a good start and let's you 'roughly' approximate how 'close-to-ideal' gasses behave in simple laboratory experiments.

  290. My favorite identities by Eric119 · · Score: 1

    Arithmetic identity: 37 * 3 * 7 = 777
    Algebraic identity: a^2 - b^2 = (a + b)(a - b)
    Trigonometric identity: sin 2x = 2 sin x cos x

    Also, 2dL + N = kb + d, which doesn't mean anything to any of you because I haven't told you what the letters stand for.

  291. Best one by Spackler · · Score: 1

    P = NP

    Now, if I could just prove it!

  292. my favourite silly equations by William+Fold · · Score: 1

    ... saw these as grafitti on the engineering building walls in the university I went to.

    lim GPA = B.A. (self explanatory)
    GPA->0

    sin(x)
    ------ = 6 (the n's cancel each other out)
    n

  293. Intel's favorite [sic] equation by ziegast · · Score: 1

    I think Intel's least favorite simple equation is:

    4195835.0 / 3145727.0 < 1.3338

    Here
    are
    a
    few
    articles to refresh your memory.

  294. 0/0 = ??? by starling · · Score: 1

    Gotta love calculus.

  295. give me a break by apankrat · · Score: 1

    first proof, that i'd seen at least, of the existance of negative numbers.

    negative numbers exist by definition, dude. you start with natural numbers - 0,1,2,3,4.. and summation. once you want to reverse 'the plus', you define negative numbers. then when you want to invert multiplication, you get rationals. then when you want to invert exponentiation - you get irrationals. get it ?

    --
    3.243F6A8885A308D313
    1. Re:give me a break by jehnx · · Score: 1

      I think he's not so stupid as to not get that much of it, but I believe he was saying that its irrationality made no sense to him, and this proof helped him to realize (or believe, perhaps realize is not a good word) that these exist.

  296. This one from the teachers by cakefool · · Score: 1

    This one was e-mailed to me by a teacher
    When asked to answer a question about circular math proof(I don't know) the written answer was

    Fork + Spleen = shoe

    The student appeared to be panicking at that point in the paper.

  297. Umm, electricity has negative. by Anonymous Coward · · Score: 1, Informative

    Negative numbers exist in nature, in electricity.

  298. Newton and Navier-Stokes by afroncio · · Score: 2, Interesting

    The equation I use the most is definitely "F = m a" in all of its interesting forms. I would give that a number one rating.

    But the most intriguing are the Navier-Stokes Equations. It's amazing that just by changing the boundary conditions on these dynamical equations, you can completely change the behaviour of the flow.

    For incompressible flows of common fluids, these 3 simple equations make incredibly accurate predictions:

    du/dx + dv/dx = 0 (incompressibility eqn)

    du/dt + u du/dx + v du/dy + dP/dx = 1/R ( d^2 u/dx^2 + d^2 u/ dy^2 ) (momentum-x eqn)

    dv/dt + u dv/dx + v dv/dy + dP/dy = 1/R ( d^2 v/dx^2 + d^2 v/ dy^2 ) (momentum-y eqn)

  299. 4=5 by sicapo27 · · Score: 1
    4x + 8 = 5x + 10

    4(x+2) = 5(x+2)

    4 = 5(x+2)/(x+2)

    4 = 5

    --
    This sig is better than nothing!
  300. funny one for engineers by BobWeiner · · Score: 1

    Here's a few that harken back to my college days in elecrical engineering (EE):

    lim Engineer = Business Major
    GPA ->0

    lim EE = Industrial Engineer
    GPA ->0

    The PC Weenies: Tech toons for tech enthusiasts.

    --
    The PC Weenies: 11 Years of Online Tech 'Too
  301. If I was God... by Anonymous Coward · · Score: 0

    I would post my very best secret formula here on Slashdot, watching with a smile how it gets unnoticed and zero score, just becouse I would submit it as Anonymous Coward.

    Just a Random.Idea

  302. Maxwell and Schroedinger by aminorex · · Score: 1

    Maxwell's equations in the quaternion form are simultaneously deep, simple, symmetric, and intuitive, but for mind-expansion you can't beat the quantum wave equation.

    --
    -I like my women like I like my tea: green-
    1. Re:Maxwell and Schroedinger by Anonymous Coward · · Score: 0

      I agree completely. Maxwells 4 equasions to fully join electic and magnetic phenomena are absolute masterpieces of physics.

      Maxwell's equasions

      I've always had a fondness for Schrodinger's wave equasions too. Between the two of them they express the full spectrum of the old and new in physics prior to the introduction of flavored quarks and other such modern concepts.

    2. Re:Maxwell and Schroedinger by Mark+of+THE+CITY · · Score: 1

      For solving quantum mechanical problems (see the link to my resume), I prefer matrix mechanics. Imagine trying to find the wavefunction that describes the quantum mechanical behavior of a molecular cluster! But, with matrix mechanics, you don't have to.

      --
      The clearance system sounds logical. It is not. It is completely arbitrary. -- John Bolton
  303. Conservation of Mass Energy by PingPongBoy · · Score: 1

    x++;

    --
    Know your pads. One time pad: good for cryptography. Two timing pad: where to take your mistress.
  304. one in spanish (pun) by cabazorro · · Score: 1

    pp
    ___ = bb
    tt

    --
    - these are not the droids you are looking for -
  305. A bit of clarification by panurge · · Score: 1
    Obviously I was too terse. A little learning is a dangerous thing...
    I was objecting to P=VI. The power dissipated in an AC circuit, or indeed any circuit where the voltage is changing and inductance or capacitance is present, is neither instantaneously equal to VI, nor is the energy dissipated the integral of VI by t.
    Clearly some people were so anxious to show how clever they were, they didn't make it to the second half of the original post.


    In fact, V=IR is of limited real world use. To be really pedantic, it is the sum of all the instantaneous potential differences around a loop that is equal to the series resistance multiplied by the current. When AC is applied to real world devices like tungsten lamps, there is temperature variation of the resistive part which makes the whole equation much more complex. I stand by my original comment, which is that in real-world AC applications, which EEs come up against daily, the simple formulae are of limited use.

    And, if we are being really sticky, voltage and current are measured in vector fields. Unfortunately /. doesn't allow me to reproduce the formulae I had to master as an undergraduate, but they are more fun than the simple versions suggest.

    I don't mind people correcting my mistakes, but I do mind people who don't really know the subject trying to be clever.

    --
    Panurge has posted for the last time. Thanks for the positive moderations.
  306. favorite formula by Anonymous Coward · · Score: 0

    B4I4Q RU/18 QTpi

  307. Re: Ramanujan's Series for Pi by Zeio · · Score: 1

    Srinivasa Ramanujan: He was self-taught but had an uncanny mathematical manipulative ability. Independently, he discovered results of Gauss, Kummer and others on hypergeometric series. He is known for major contributions in Number Theory and Modular Function theory.

    Ramanujan worked out the Riemann series, the elliptic integrals, hypergeometric series and functional equations of the zeta function on his own. On the other hand he had only a vague idea of what constitutes a mathematical proof, and occasionally did state incorrect results.

    Ramanujan was reported to have dreams where Indian deities would paint this an other equations in blood on his mind.

    This formula as far as I can tell came from nowhere but a strangely tuned up mind

    http://www.bath.ac.uk/~ma2lg/project/ramanujan.gif

    Slashdot's inferior "lameness" filter won't allow formulas to be written textually with elegance.

    1/pi = [sqrt(8)/9801] * summation of variable i from 0 to infinity [{(4i)! [1103 + 26390i]} / {(i!)^4 (396)^4i} ]

    Where there sqrt(8)/9801, 1103, 26390, 396 all come from is anyone's guess. The thing generate 8 places of pi every cycle.

    Edward Witten's work on unifying the string theories is another set of equations that probably deserve mention, but the practical use for Ramanujan's series and the Chodnovsky improvements to it are undeniable.

    Archimedes understood infinity and how to work out the volumes of shapes around 212 BC (The year of his death - he was killed by a Roman soldier invading Syracuse when he said; "Stop disturbing me and my circles!" The soldier was supposed to take Archimedes custody and bring him to Rome).

    He has written a book called, The Method, the last surviving copy of it was overwritten for prayers in 1000AD, and then the manuscript was partially discovered in the early 1900's, and just now is the rest being restored using modern technology. Archimedes understanding of infinity and the fundamentals of Calculus would take humanity until Newton / Leibniz, the modern world is probably "off" by possibly 500 years due to The Method having been lost.

    --
    Legalize the constitution. Think for yourself question authority.
  308. As a martial artist... by fyngyrz · · Score: 1
    ...my favorite is K = M(over 2) V(squared)

    Combine that with using the smallest, hardest striking surface you can deliver, and you understand why perfectly good bricks can be broken when struck correctly.

    You also intuitively understand why it is best not to try to mug someone who seriously studies a striking art.

    :)

    --
    I've fallen off your lawn, and I can't get up.
    1. Re:As a martial artist... by PingPongBoy · · Score: 2, Funny

      I see the unstoppable and the immovable - now what do I need to do to chop a brick?

      --
      Know your pads. One time pad: good for cryptography. Two timing pad: where to take your mistress.
    2. Re:As a martial artist... by fyngyrz · · Score: 1

      I suggest - a hammer. :)

      --
      I've fallen off your lawn, and I can't get up.
  309. GLAT by kwatz · · Score: 1

    Looks like somebody was having trouble with question #12...

  310. Wow: Try this in Google! by rpcxdr · · Score: 2, Informative

    Who needs a calculator anymore? Google cannot be stopped:

    e^(pi*i)+1

    1. Re:Wow: Try this in Google! by Pharmboy · · Score: 2, Informative

      actually, been using the calculator available in my.yahoo.com for many years now. and its a bit more intuitive.

      --
      Tequila: It's not just for breakfast anymore!
  311. My favorite by xmpcray · · Score: 1

    Speed=Distance/Time

    Quite useful you know...

    --

    --
    I refuse to answer that question on the grounds that I don't know the answer.
  312. oh yah? well.. by Anonymous Coward · · Score: 0

    There are 10 kinds of people in the world

    Those who understand trinary
    Those who dont
    and those who mistake it for binary.

  313. OTS and Fibonacci by jskelly · · Score: 1
    Favorites include Fibonacci -- surely one of the greatest of all time, due to its relationship with the golden section/golden mean.


    Other favorite is the pseudoscience behind marketing industry equations like
    opportunities to see (OTS). I can never remember these offhand because they are so meaningless, but it is fascinating to think of the millions of dollars spent on ie outdoor billboards, where the advert is sold on the basis of these "opportunities to see." See also A Test of the Direct/Indirect BBD and Other Exposure Distribution Models.

  314. My personal favorite... by Aggrav8d · · Score: 1

    As any mathematician who's ever been on a date might have wondered:

    b 4 i root(u) r u / 18 ?

  315. You mean 55318008 by lashi · · Score: 1
    >Oh well. 5318008

    I am only slightly ashamed that I spotted that error.

    1. Re:You mean 55318008 by Edax+Rarem · · Score: 1

      Well, the poster was spelling "boobies", while you missed spelling "boobless".
      "55378008" seven, not one.

      Now who is more ashamed. ;->

      --
      I hate my sig.
    2. Re:You mean 55318008 by lashi · · Score: 1
      > Well, the poster was spelling "boobies", while you missed spelling "boobless".

      See, I am too innocent to know all these dirty things. Thank you, thank you, thank you, I feel so cleansed!

  316. An anagram equation by thelenm · · Score: 2, Interesting

    This one I find interesting because the two sides are not only equal, but anagrams of each other when spelled out in English:

    11 + 2 = 12 + 1

    ELEVEN + TWO = TWELVE + ONE

    --
    Use Ctrl-C instead of ESC in Vim!
  317. favorite equation contest = lame by Anonymous Coward · · Score: 0

    that's my favorite

  318. Division by zero, and other oddities... by DigitalEntropy · · Score: 1

    My friends and I back in high school would argue constantly over the following equation:

    0/0 = 1

    Or at least, that's the case I keep trying to make: that the ratio of nothing to nothing is indeed, one. However, alternative principles instruct that ANYTHING divided by 0 is undefined. Yet when graphed on a cartesian coordinate system, a function like 'x = y/0 + a' dictates that for every y, there is a vector or dimension perpendicular to x at a (which is, inherently, a value of x). It basically defines an infinite open-ended ray at a 90 degree angle to x.

    It is indeed undefined how to express this. "[+/-] infinity" would be my best guess. But then I guess I'd have to update my equation to:

    0/0 = [+/-] 1

    Which, is structurally sound if you accept that 0, in being neither postive or negative, can also be said to be both simultaneously. The net effect, of course, is nothing. Yet principally, it illustrates a sort of "optional" element of math, wherein the questionable pre-existing values (such as sqrt(x)) are determined in relation to the answer AFTER completion, or otherwise ambiguously tagged with [+/-].

    x = y + 2

    for:
    x = 0; y = -2

    x/0 = (y + 2)/0

    [+/-] 1 = (-2 + 2)/0

    [+/-] 1 = [+/-] 1

    Anyone else care to participate in some junk math? :)

    --

    Thank you for reading One Man's Opinion. No participation necessary. Offer void where deemed by law or PATRIOT Act.
  319. the only one that matters by Anonymous Coward · · Score: 0

    hey baby you + me = calculus

  320. Re:favorite equation by Anonymous Coward · · Score: 0

    In the context of the upcoming election, my favorite equation is one of Niven's Laws:

    F dot S = K

    aka the product of freedom and security is a constant.

  321. Formula for Love, Yin & Yang by cfoster70 · · Score: 1

    Looking to tell that special geek in your life how much you care? The following inequality graphs the shape of a heart:

    r - 0.2e^(-10 | theta - 1.5 * pi |) < root( 0.5 * (1 + cos( theta + 0.5 * pi ) ) )

    And this one makes the yin & yang symbol:

    (cos (theta - r) - sin theta)(r^4 - 2r^2 cos( 2 * theta + 2.4 ) + 0.9) + (0.62r)^1000 < 0

  322. Maxim by tchdab1 · · Score: 1

    2*(wrongs)~=(right)

  323. Best Equation Ever... by 2names · · Score: 1
    A * D = O

    A => ass in kg
    D => Entry angle in degrees
    O => Wave vector of highly saline, large volume of H2O

    In other words,

    "The Mass of the Ass times the Angle of the Dangle equals the Motion of the Ocean."

    :)

    --
    "I'm just here to regulate funkiness."
    1. Re:Best Equation Ever... by DickBreath · · Score: 1

      The angle of dangle is proportional to the heat of the meat divided by the mass of the ass squared.

      --

      I'll see your senator, and I'll raise you two judges.
  324. Comment removed by account_deleted · · Score: 1

    Comment removed based on user account deletion

  325. The breast equation by Explo · · Score: 1

    Well,

    the breast equation sounds pretty interesting.

    Got to try to visualize it someday to see how well it corresponds with the reality.

    --
    Everyone who makes generalizations should be shot.
  326. All the good stuff. by grmoc · · Score: 1


    (e^(2 * pi * i)) - 1 = 0

    Contains, e, pi, i, 2, 1, and 0.

  327. it is right.... by rbird76 · · Score: 1

    Why do chemists use an unattractive form of the Ideal Gas Law? Well, using numbers ending in 6.022e23 is kind of inconvenient for any mass of material that a chemist would use on a daily basis. Chemists work with mg-kg of material; at those scales, counting particles as a unit of mass is impractical and inconvenient. It's better instead to convert to units that approximate the unit scale on which one works.

    Physicists are likely to deal with particles, hence the use of particles as a unit is reasonable, in addition to the fact that they are more likely to work with equations that get ugly when using molar units (the same goes for some physical chemists). For most chemists, molar weights are a far more useful measure of mass than particles would be. The beauty of the IGL if particles were used as the unit is far outweighed by the awkwardness of the use of particles as units for most things chemists do.

    The additional factor is the IGL is only an approximation - a good starting point for understanding how gases behave, but not useful for high precision measurements, at low temperatures or at high pressures. The more accurate versions of the IGL for these circumstances are much uglier. Changing things for the sake of the IGL, in this case, is like sacrificing one's schedule to be with an accurate doll rather than a girlfriend/SO - you would be altering a useful units system for an equation that is interesting but has lost much of what is real about the phenomena it models.

    yes, I am a chemist....

  328. I'd vote for ... by Muad'Dave · · Score: 2

    1 + 0 = 1

    The realization of zero was a major breakthrough, IMHO.

    --
    Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
  329. My fav = Idiot Businessman's Equation by fbg111 · · Score: 1

    x + y + ??? = Profit!!!

    --
    Flying is easy, just throw yourself at the ground and miss. -Douglas Adams
  330. y=mx + b by hey! · · Score: 1

    Yeah, simple I know, but I love the way it takes a line and converts it to two simple parameters.

    I use this equation a lot of times by way of analogy. I often draw little graphs in management meetings where we are discussing the merits of different strategies and discussing the relationship between initial investment, marginal costs and planning horizon.

    It's very simplistic I know, but it turns out that drawing a picture can often change the framework in which people make decisions, even if the mathematics is not precisely right. Many people one works with are not inclined to think about decisions mathematically, but they can understand that a line can be described by slope and intercept, thanks to the efforts of the benighted Algebra teachers of yore.

    --
    Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
  331. my favorite is by Anonymous Coward · · Score: 0

    Use on females:

    U + I = 69

  332. maxwell's equations by superstick58 · · Score: 1
    I'm surprised I don't see any mention of Maxwell's equations. From these, any equation involving electronics can be derived. Of course I wouldn't want to go through that process.

    How about this one: limit as GPA -> 0 of F(engineering) = Y(business)

    1. Re:maxwell's equations by iggymanz · · Score: 1

      you can derive special relativity from Maxwell's equations too. I had a professor once show quantizing the EM field in M.E. to produce most of electroweak theory, but maybe he was pulling a fast one, that was a little beyond me.

  333. where's the n? by bodrell · · Score: 1
    I read through the article, and looked at the graphic, and found no mention of "n". But I agree with another poster that the really elegant equation is the full form, with sines and cosines. Then plug in pi and it reduces to e^i*pi = -1.

    That really blew my mind when I first saw it in high school, and it made no sense at all until I saw the Taylor series of e^x, vs. those of sine and cosine. But man, is it easier to work with exponentials than with sinusoids. Just like it's a lot easier to work with Laplace transforms via arithmetic than to try to manually solve differential equations.

    The Wikipedia article shows the Taylor series expansion proof.

    --
    Si la vida me da palo, yo la voy a soportar Si la vida me da palo, yo la voy a espabilar
  334. Favorite equation! by E+IS+mC(Square) · · Score: 1

    Sometimes, only the name is enough.. :-).

    At last...

  335. Course 2? by Anonymous Coward · · Score: 0

    I thought that was course 1.

    1. Re:Course 2? by rpillala · · Score: 1

      it is :)

      Welcome to the reality of high school.

      --
      When the axe came to the forest, the trees said, "Look out - the handle was once one of us."
  336. For word freaks... by Anonymous Coward · · Score: 0

    TWELVE + ONE = ELEVEN + TWO

  337. Z = R + jX by Anonymous Coward · · Score: 0

    Charles Proteus Steinmetz(read the last item on the page 1st) took on old theoretical idea of complex numbers (real + imaginary)
    a + bi
    and turned it into a way to quantify impedences in alternating current circuits
    Z = R + jX

    gewg_

  338. Heard on Car Talk This Weekend by Marxist+Hacker+42 · · Score: 1

    Unfortuneately I can't type it adequately as I don't have the HTML tag for SuperScript memorized:

    Write the integers 2,3,4,5 with one plus sign and one equals sign as an equation.

    Answer (replacing the superscript with ^) 4+5=3^2

    --
    SJW: a person who perceives an injustice, and while correcting it, commits a greater injustice.
  339. e=mc^2 by CaptainTux · · Score: 1
    While I'm not too sure I actually *have* a "favourite equation* I'd have to say that the simple one in my post subject would come very close.

    Why is it my favourite while being so simple? Because its elagance lies in its very simplicity. There are not many other equations that have so much power yet are so simple that a child with very little formal education can quickly learn and understand it.

    --
    Anthony Papillion
    Advanced Data Concepts, Inc.
    "Quality Custom Software and IT Services"
  340. 1+1=2? by Anonymous Coward · · Score: 0

    c'mon. we all know 1 + 1 = 0 (with an overflow)

    1. Re:1+1=2? by SmurfButcher+Bob · · Score: 1

      1 + 1 = 0 (with an overflow) and an exploit two days later.

      --

      help me i've cloned myself and can't remember which one I am

  341. May the Force Be With You by Anonymous Coward · · Score: 0

    "May the force be with you and may the sum of the forces equal zero"

    -Bounced around the Naval Academy in the mid '80s

  342. Circumference of a pumpkin divided by its diameter by Anonymous Coward · · Score: 0

    The circumference of a pumpkin divided by its diameter = pumpkin pi.

  343. My favorite equation? by NanoGator · · Score: 1

    "Windows really sucks, I hope they burn in the afterlife!" == (Score: 5, Insightful)

    "Linux could use a little bit of improvement." == (Score -1, Troll)

    --
    "Derp de derp."
  344. Ah, Algebra I... by niteice · · Score: 1

    y = mx + b. So simple, yet, I never got algebra.

    --
    ROMANES EUNT DOMUS
  345. My favorite equation... by Anonymous Coward · · Score: 0

    0 + .l. + 0 = yummy... that's my equation for an FMF threesome!

  346. Re:Submitter and Parent are stupid by Dahan · · Score: 1
    The parent said Exp(i*PI) +1 = 0, but Exp(2*Pi)= +1, not -1....

    Better get your calculator fixed. Exp(i*Pi) + 1 is equal to 0, and Exp(2*Pi) = 535.491655524764736503...

  347. The MIT cheer? by Anonymous Coward · · Score: 0

    e^x dy dx e^x dx
    tangent(secant(cosine(sine(3.14159)))
    Go Tech, Go!

  348. 0.99999... = 1 by ProKras · · Score: 1

    Here's a simple proof: 1/3 = 0.33333... 0.333... + 0.333... + 0.333... = 0.999... 1/3 + 1/3 + 1/3 = 1 0.333... + 0.333... + 0.333... = 1/3 + 1/3 + 1/3 0.99999... = 1 It can also be proven with limits and stuff, but this proof is easier. Strange things happen when you start dealing with infinities.

    1. Re:0.99999... = 1 by ProKras · · Score: 1

      oops meant to post this as plain text. should look like this:

      Here's a simple proof:

      1/3 = 0.33333...

      0.333... + 0.333... + 0.333... = 0.999...

      1/3 + 1/3 + 1/3 = 1

      0.333... + 0.333... + 0.333... = 1/3 + 1/3 + 1/3

      0.99999... = 1

      It can also be proven with limits and stuff, but this proof is easier.

      Strange things happen when you start dealing with infinities. And they look even stranger things happen when you screw up the formatting

  349. I swear to goodness by Degrees · · Score: 1
    I recently saw a SBC van painted a pale blue with white letters, five foot high, with the marketing slogan: 1 + 1 = 1

    Fricken' idiots - and no, I won't be their customer any time this next century....

    --
    "The most sensible request of government we make is not, "Do something!" But "Quit it!"
  350. Natural Cubic Splines by dprust · · Score: 1

    In my opinion, one of the most beautiful equations is the one that computes natural cubic splines. Given a set of knots (points) on a graph, this equation figures out a smooth curve between each point. This is called "curve-fitting". Very cool calculus, and it includes a tridiagonal matrix equation, which gives it extra beauty points! See this page for an excellent discussion on it:

  351. Some of my favourites by Krakhan · · Score: 1

    Cauchy-Schwarz Inequality: For any x and y in an inner product space,

    <x,y> <= ||x|| ||y||

    Very useful in a lot of branches of mathematics.

    Also, the every so interesting identity,

    SUM{n=1, infinity}( 1/n^2 )= (pi^2)/6

    Very interesting how pi shows up where you least suspect it!

  352. Re:correction - Now we are getting really OT by Anonymous Coward · · Score: 0

    Actually, Bud Adams would not release the rights to the name Oilers and so the City of Houston had to pick something else.

  353. My favorite by Ted+Stoner · · Score: 1

    a ** x = e ** (x ln a)

    Much prettier than a lot of the other equations I've seen here.

  354. Incorrect by Anonymous Coward · · Score: 0

    De Moivre theorem DOES NOT contain e:

    i sin(n x) + cos (n x) =[i sin(x) + cos(x)]^n

    De Moivre 17th Century

    Euler 18th Century

    De Moivre was a French protestant who immigrated to England to escape religious persecution. He died poor. Euler died filthy rich, the emperor of Russia paid him a huge salary.

  355. Definitions vice equation by jamej · · Score: 1

    Dude, 1+1=2 is a matter of definition not a "free standing" equation, e.g., in binary 1+1=10. I vote for E^(ipi)+1=0 that equation ties so much to together. The first time I saw it derived was a cathartic experience. A puely personnel reason for my vote. But, I'll never forget that moment.

  356. Come On Computer Guys!!! by Anonymous Coward · · Score: 0

    1 + 1 = 0 in binary when you only have one bit, lousy overflow!!!

  357. They're the same thing. by Otto · · Score: 1

    1/3 = 0.333333...
    2/3 = 0.666666...
    3/3 = 0.999999...
    Yet we are always told that 3/3 = 1


    Try subtracting 0.9999999..... from 1.

    1 - 0.999999... = ???

    If you can come up with any other answer than 0, then I'll think you're onto something. :-)

    --
    - Give a man a fire and he's warm for a day, but set him on fire and he's warm for the rest of his life.
  358. Equation of proof of age in Australia by Anonymous Coward · · Score: 0

    b4 i u^0.5 (ru)/16 QT Pi

  359. From Gary Larson . . . by Anonymous Coward · · Score: 0

    4(Wr)^2-2Wr^4/((x-y)^2+(y-????? = r

    caption from the cartoon "Yes, yes, I know that, Sidney..._very_body knows _that_!...But look: Four wrongs _squared, minus two wrongs to the fourth power, divided by this formula, _do_ make a right."

    gdfj12

  360. Tell your boss by Baby+Duck · · Score: 1

    Work is mass accelerated over a distance.

    W = mad

    Work is mad! mad I say!

    --

    "Love heals scars love left." -- Henry Rollins

  361. g=9.8 m/s^2 by doomtiki · · Score: 1

    I NEED gravity almost as much as I need my computer.

  362. 1+1=window by David+Hartigan · · Score: 1

    1+1=window

  363. P=VI by philfr · · Score: 2, Funny

    If vi is power, what about emacs ?

  364. Jjjjeeewwwweeeellllsssss by readpunk · · Score: 1

    F=MA think sex.

    --

    ./revolution
  365. the joke... by Anonymous Coward · · Score: 0

    ...wasn't funny to either type actually

  366. Drakes Equation by C60 · · Score: 1


    N = N* fp ne fl fi fc fL

    Okay, it may sound corny, but even with relatively low numbers, it still gives me hope that there is someone out there smart enough to leave us alone.

    --
    Karma: 0 (But I wield a mean +10 Vorpal Apathy)
  367. how about these apocalyptic equations? by e_xworm · · Score: 1

    like this (the sum of squares of the 7 first prime numbers)

    2^2+3^2+5^2+7^2+11^2+13^2+17^2=666
    or this(the sum and difference of the first 3 6th powers)

    1^6-2^6+3^6=666
    eeek this starts giving me the chills

    --
    X~
  368. yes but by Anonymous Coward · · Score: 0

    anything involving computers (i.e. transistors) is not one of them

  369. conservation equation: the ultimate GP supporter by Anonymous Coward · · Score: 0

    if rho is a scalar field than if:
    d(rho)/d(t) + grad(rho*position vector) = 0 in a region
    than the integral of rho over that region is a constant.
    Sorry guys just got my physics degree on Saturday.
    P.S. d-> partial derivative

  370. Not hard to add! by weston · · Score: 1

    Considering most 3-D rendering engines make heavy use of vector mathematics, all you'd really have to do is develop the interface.

    Not that you necessarily *want* players doing arbitrary transforms on the gaming environment, but hey, I think it'd be fun.

  371. jeez what a bunch of dilitanttes by Anonymous Coward · · Score: 0

    screw you. n/t

  372. You're all wrong by multipartmixed · · Score: 2, Funny

    > Euler's Formula is breast milk??

    No, it's

    99 + 20 + 9 + 6 + 15 + 31 + 21 + 23 + 22 + 26 + 17 + 19 + 4 + 14 + 24 + 33 + 11 + 28 + 18 + 5 + 10 + 32 = 1 * (Stanley Cup)

    You're welcome.

    --

    Do daemons dream of electric sleep()?
  373. lets see by geekoid · · Score: 1

    Pi + HoMer = 0Pi
    Wine + Flowers = SEX
    2 + 2 = 4096
    0 - 1 = -1
    infinity/2 = infinity

    --
    The Kruger Dunning explains most post on /. http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
  374. The Management Equation by FrankieBoy · · Score: 2, Funny

    A mathematical proof which explains why managers and others in authority make so much money.

    From your physics course, you will recall that:

    Power = Work / Time

    From the world of business, we know that:

    Knowledge = Power

    and also that:

    Time = Money,

    Substituting these identities into the original equation, we get:

    Knowledge = Work / Money

    Solving for money, we get:

    Money = Work / Knowledge

    Thus, Money approaches infinity as Knowledge approaches zero, regardless of the Work done.

    What this means is: The Less you Know, the More you Make.

    Taking this analysis and proof one step further, we know that:

    Knowledge = Education x Time

    Solving for Time:

    Time = Knowledge / Education

    and then substituting for Time back into the Power equation, we get:

    Power = (Work x Education) / Knowledge

    From which we can see that the closer Knowledge gets to 0, the more power one will have.

    Note:You can also increase Power through increasing either Work or Education, but it should be noted that this approach doesn't have the same type of leverage as lack of knowledge.

    This equation is also known as the MANAGEMENT equation, since it provides a clear and concise mathematical explanation of why managers, executives, politicians and most other highly unknowledgable individuals get paid so much.

    Also explains why us highly knowledgable techies get paid nothing.

  375. MathML by sexecutioner · · Score: 1

    How much nicer would all these posts be if we had real MathML suport!!!

    Here is what Mozilla is doing about it, but is any other browser supporting this [much needed!] standard?

  376. physical geometry by Brutal_Adviser · · Score: 0

    The angle of the dangle is inversely proportional to the heat of the meat.

    --
    Tone
  377. PARENT + MOD POINTS = HAPPINESS by jolyonr · · Score: 1

    I've got mod points but I can't use them here, so unfair!

    --


    Please read my Canon EOS tech blog at http://www.everyothershot.com
  378. My favourites by Pseudonym · · Score: 1

    My favourites are the Lagrangian (and Hamiltonian, for that matter) formulation of Newtonian dynamics. The Lagrangian one is: d/dt(dL/dq') + dL/dt = Q (where all derivatives are partial)

    Not only does this sum up all of Newtonian mechanics, it also has the Newtonian part of Noether's theorem as a trivial corollary.

    Noether's theorem, for the uninitiated, is a very deep law of nature. It states, more or less, that for every symmetry in a physical system, there is a corresponding conserved quantity. Examples:

    • If it doesn't matter where you perform an experiment, then momentum is conserved.
    • If it doesn't matter when you perform an experiment, then energy is conserved.
    • If it doesn't matter what phase your waves start at, then electric charge is conserved.
    --
    sub f{($f)=@_;print"$f(q{$f});";}f(q{sub f{($f)=@_;print"$f(q{$f});";}f});
  379. Even better one by Anonymous Coward · · Score: 0

    "Its like asking what's the square root of a million. No one will ever know"

  380. Euler was the greatest mathematician by Schwarzchild · · Score: 1

    of the modern era. Mathematicians at St. Petersburg were still publishing his stuff seventy years after he died. I sometimes see mathematicians claiming that Gauss was the greatest but I don't think he stacks up against Euler.

    --

    "sweet dreams are made of this..."

  381. Stirling's formula for factorials by Fortran+IV · · Score: 1

    is one of the weirdest I've ever seen, another one that brings pi and e together.

    n! = ((n/e)^n)*sqrt(2*pi*n)

    It's only approximate, but it gets more accurate (relatively) as n increases.
    --
    I figure by 2030 or so my 6-digit UID will be something to brag about.
  382. best of all by marianne1017 · · Score: 1

    P = NP

  383. Sci-Fi blog scooped us by 10 whole days! by Anonymous Coward · · Score: 0

    This was posted TEN WHOLE DAYS ago (08:28 PM:, 15 Oct 2004) at the blog Making Light. Are we gonna let a bunch of Science Fiction writers and editors get away with being nerdier than us?

    The Nerdier, Newsier Blog Jonathan Vos Post ::: (view all by) ::: October 15, 2004, 08:28 PM: "... Great equations change the way we perceive the world. They reorchestrate the world -- transforming and reintegrating our perception by redefining what belongs together with what. Light and waves. Energy and mass. Probability and position. And they do so in a way that often seems unexpected and even strange...."

  384. props for Godel by ckromero · · Score: 1

    not an equation per se but a core statement from a theorem:
    "This statement is unprovable."

    sweet

    --
    ...would I lie to you?
  385. My favorite is a seasonal equation by bgspence · · Score: 1

    Halloween is the same as Christmas because:

    Oct 31 = Dec 25

  386. I like.... by march · · Score: 1
    I like the integral of e^x because it is a function of u^n:


    /-\
    | x n
    | e = f(u )
    |
    \-/
    :-)
    1. Re:I like.... by march · · Score: 1

      Ok, so /. doesn't like the PRE tag, and I hit submit instead of preview. Alas... Anyway, I leave the formatting as an excercise to the reader. :-)

  387. Small Erorr... by atrader42 · · Score: 1
    You said: And because "money is the root of all evil" we therefore can state:
    Money = (Evil)1/2
    And Since
    (Money)2 = Women
    Then (Money)2 = Evil
    And we are forced to conclude by substituting "women" for "(money)2" from above that:
    Women = Evil

    But you're skipping a step that changes the solution....

    Money = Evil^(1/2)
    then
    Money^2 = (Evil^1/2)^2
    Women = Money^2
    Women = (Evil^1/2)^2
    so....

    Women = +/- Evil

    The practical applications? Confusion, angst, and our eternal love/hate relationship with that species.

  388. Identity by r2q2 · · Score: 1

    How about any equasion that shows an identity or the most simple 0=0 to a more complex one. I guess this is a group of equasions but I think they are the most beautiful.

    --
    My UID is prime is yours?
  389. central limit theorem by Anonymous Coward · · Score: 0


    I've always been very impressed with the central limit theorem, which states that the sum of a large number of random variables is approximately normally distributed -- regardless of the distribution of the individual random variables.

    The CLT basically explains why the normal distribution appears so often -- since large systems usually combine a large number of random variables together.

    Off the top of my head, I would guess that the formula for the CLT is something like this:

    Y = lim(n->infinity) SUM(i=1..n)X(i) -> Y ~ N(mu,sigma^2)

    Plus auxiliary formulas to define mu and sigma^2.

  390. 0.99999... = 1 by Anonymous Coward · · Score: 0


    I like:

    0.99999... = 1

    Which is easily proven by:

    x = 0.99999...
    10x = 9.99999...
    9x = 9 (subtract the 1st from the 2nd)
    x = 1
    QED

  391. Best TShirt ever by SmurfButcher+Bob · · Score: 1

    ...And God Said,

    E.dA = q/e0
    B.dA = 0
    E.ds = -d/dt( B.dA)
    B.ds = m0.( I + d/dt (e0. E.dA))
    ... and there was light.

    Dammit, integral symbol won't render :(

    --

    help me i've cloned myself and can't remember which one I am

    1. Re:Best TShirt ever by earlejones · · Score: 1

      Woody Allen said: "In the beginning, there was nothing. And God said, "Let there be light." And there was light. There was still nothing, but you could see it a lot better."

  392. O.o by Anonymous Coward · · Score: 0

    (1)+(-1)=0

    mmmmm proof of existence

  393. Zero isn't a number ... by Anonymous Coward · · Score: 0

    "... 5 most important numbers ..."

    Funny, it's my understanding that zero isn't considered a number ...

  394. Fermat's Last by BakaBaka · · Score: 1

    For sheer ballsiness, I have to admire Fermat's last theorem, even though most of the proofs offered are flawed. Euler's work is pretty cool, though.

  395. S = K ln W and its relative C = w log2(1 + S/N) by Beryllium+Sphere(tm) · · Score: 1
    The first is what Boltzmann wanted on his tombstone. It connects thermodynamic entropy to statistics. It says the entropy of a system is proportional to the log of the number of possible states.

    The second is Shannon's theorem. It says the ultimate information carrying capacity of a channel is the bandwidth times the log of the number of states you can distinguish over the noise.

    These may actually be more fundamental to reality than E = mc**2.

  396. Moo by Chacham · · Score: 0

    Did you forget

    (x^y)-((x^x)/y)*C(#78b)

    1. Re:Moo by earlejones · · Score: 1

      (x^y)-((x^x)/y)*C(#78b) is not an equation, is it? earle *

    2. Re:Moo by Chacham · · Score: 0

      Isn't that what it very well addresses?

    3. Re:Moo by earlejones · · Score: 1

      Sorry -- I guess I need an explanation. Thanks, earle

    4. Re:Moo by Chacham · · Score: 0

      OK, by getting serious you're taking the fun out of it. :)

      I just wanted to see what i could type.

      And you have no JEs, so i couldn't get your attention there. :-P

  397. Re: Ramanujan's Series for Pi by Keith+McClary · · Score: 1

    This formula as far as I can tell came from nowhere but a strangely tuned up mind

    Are you saying there is no proof of the formula?

    I've read that Hardy invited Ramanujan to England where he quickly succumbed to British food and weather.

  398. Laplace's equation and conservative fields by vuo · · Score: 0
    Laplace's equation and the knowledge it's applicable to electric, thermal and gravitational (conservative) fields is the most elegant truth I know:
    nabla^2 F = 0
    I can't see the thing about the "Euler formula" (e^i*pi=-1). It's just a special case of the extension of the definition of the exponential function.
  399. 6x9=42 by PhilHibbs · · Score: 1

    I also have this T-Shirt, which I think is cool.

  400. Best One by Anonymous Coward · · Score: 0

    integer divide by zero!

    bwhahaha.

  401. bijection? by Anonymous Coward · · Score: 0

    so what of bijections vs surjections and injections?

    GrimRC

    1. Re:bijection? by fatphil · · Score: 1

      A function is a set F of ordered pairs [x,y], x \in X, y \in Y, such that for all [x1,y1], [x2,y2] \in F, x1=x2 -> y1=y2.

      The conventional notation for [x,y] being in F is f(x)=y. (The conventional notation for an ordered pair is angle brackets, but I hate typing HTML entities.)

      Therefore the definition of a function is that it is uniquely valued everywhere it is defined, i.e. if f(x)=y, then f(x) is not z for any z!=y.

      Surjections are functions such that for all y \in Y, there exists an x \in X such that [x,y] \in F.

      Injections are functions such that for all [x1,y1], [x1,y2] \in Y, y1=y2 -> x1=x2

      Bijections are surjective injections.

      FP.

      --
      Also FatPhil on SoylentNews, id 863
  402. Are there more Ramanujan-like equations? Possibly by Anonymous Coward · · Score: 0
    Taylor's neperian logarithmic of (-1) = (Ramanujan's PI) * i

    (function of real number) = (imaginary part of the complex number)

    Shortly ...

    ln(-1) = PI * i
    sqrt(-1) = 1 * i
    ...

    PI = (Taylor's eulerian logarithm of -1) * -i
    PI = (Euler's taylorian logarithm of -1) * -i
    PI = Ramanujan's equation

    Who did first invent the equation of the longest real of PI?

    Thanks to Ramanujan, Taylor & Euler, Cheby???chev, Cauchy, ...
    Can we find quicker equations of any polynomial or function?
    Possibly, but it's not easy to find ... ;)

    open4free ©

  403. "Proof" that 1 can be both singular and plural by JamesGecko · · Score: 1
    I think my favorite equation would have to be Bill Sneed's mathematical proof that one can be simultaneously singular and plural. (Shamelessly ripped off of OpinionJournal's "Best of the Web Today")

    Let a=1

    Let b=1

    Therefore a=b

    Multiplying both sides by a gives a^2=ab

    Subtract 1 from the left and b (which equals 1) from the right: a2-1=ab-b

    If you remember your quadratic equations, this factors to: (a+1)(a-1)=b(a-1)

    Dividing both sides by a-1, we have a+1=b, or 1+1=1

    Therefore 2=1

    To be sure, this is a counterintuitive result, and math purists will no doubt find fault with it. Well, I just have three words to say to them: E pluribus unum. Got a problem with America, Math Boy?

  404. Best equation by TheM$Man · · Score: 0

    This is by far the best equation ever made. (B + I) * (L^2) * (G / A) + (T - E) * S = M$

  405. My favorite (another sex joke) by ekolis · · Score: 1

    My favorite equation is: Derivative of e to the x = e to the x plus C Not quite mathematically correct (missing a "dx" before the equals sign) but if you write it out, it spells "Sex = Ecstasy" :D

    --
    Oh dear, Mr. Flibble, we can't do anything like THAT... who would be left to clean up the MESS???
  406. Favorite Equation by earlejones · · Score: 1

    Augustus deMorgan told us:

    log(-1) / sqrt (-1) = C / D

    where C and D are the circumference and diameter of a circle.
    Both terms on the left side are imaginary; both on the right side are real!

    earle
    *

  407. ob simpsons by Lord_Breetai · · Score: 1

    Hey, "gotta be a winner" is wrong....

    "A WINNER IS YOU" is correct!


    obligatory simpsons quote:

    Toy pinball machine: "Ha Ha Ha! You a winna!! Ha Ha Ha! You a winna!! Ha Ha Ha! You a winna!!"

    --
    "You are only young once, but you can be immature forever." -www.animemusicvideos.org
  408. How to pronounce "G = H - TS" by KWTm · · Score: 1

    The Gibbs free energy equation, G = H - TS, is pronounced "Garlic is Hell without Tartar Sauce"

    --
    404555974007725459910684486621289147856453481154 in hex is "You sank my Battleship?"
    [GPG key in journal]
  409. Re:Something most of you will not never understand by CaptainAvatar · · Score: 1

    I think I understand the sentiment, but I have no idea what that stupid equation is supposed to prove.

    --
    The real Captain Avatar is a fictional character, so I suppose he doesn't mind if I impersonate him.
  410. Re: Ramanujan's Series for Pi by Zeio · · Score: 1

    It's been proven here:

    http://citebase.eprints.org/cgi-bin/fulltext?forma t=application/pdf&identifier=oai%3AarXiv.org%3Amat h%2F9306213

    But from what I understand, this guy came up with most of his best work with only a vague idea of what a mathematical proof was.

    He did get invited to England, was decorated academically but did die of disease brought on by an intense dislike of the food and he was not aware of how to properly sleep under covers, and the cold nights caused his health to deteriorate along with malnutrition.

    This is not a joke, I've read somewhere reliable that he was never told how to properly put himself to bed - he slept without the covers never knowing (or being shown for that matter) how the bed was to be used.

    Apparently, the first 3-4 letters received in England were thought of as hoaxes because he had his own notation for everything, but it was (luckily) discovered that he was no hoax.

    --
    Legalize the constitution. Think for yourself question authority.
  411. Re:whatthe? by RocketRainbow · · Score: 1

    Why am I not surprised that this was posted anonymously? And for the record, I'm raising a baby, so I've got books full of stuff about allergies. The main ones are: shellfish, eggs, milk, peanuts, chocolate, any kind of animal flesh, and then wheat and corn. Wheat and corn are full of vitamins, but the same vitamins are to be found in many less allergenic grains such as spelt, quinoa, amaranth, rice, and so on.

    The human organism is a herbivore. But much like chimpanzees, we require trace quantities of vitamin b12. Well so what? Chimps get it from shit - they don't wash their vegetables, and from insects - they don't wash their fruit. I choose to get mine from a supplement but I could eat an egg or a glass of milk every couple of weeks if I didn't think that was GROSS!!

    Animal flesh sits in your colon festering. It's really yucky. A carnivore has a really short intestine with really acidic stomach juices to digest it and get it out. Anywho, I eat just fine.

    If the land is unsuitable for growing crops then it's about 7 times more unsuitable for grazing animals.

    The food with the highest proportion of protein is the nut. Then come the legumes. Then comes (yuck) the animal flesh.

    Actually, I'm a vegetarian because I don't want to eat animal flesh AND I DON'T HAVE TO!!! It's quite a relief to know that I don't have to - I was quite concerned until I did enough research.

    If you keep eating that crap it won't necessarily kill you... it's not the most dangerous thing people do. But it's pretty bad, actually. But I guess it's your own business.

    --
    *#*#*#*#*#******* I love peanut butter sandwiches!
  412. Not a math equation by daemonsito · · Score: 1

    That would be "Food + Heat = Cooking" by Alton Brown

  413. Adams Formula by kc0dxh · · Score: 1

    L+U+E=42

    --

    --- "1.21 Jigawatts!" -Doc