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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?"

51 of 1,017 comments (clear)

  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 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.

    2. 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?
    3. 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.

    4. 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.

    5. 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.

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

      A hockey team in Edmonton, Alberta...

    7. 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
    8. 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?
    9. 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.

    10. 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.
  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 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.
    2. 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...

  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 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
    2. 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
  4. 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 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

  5. 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.

  6. 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!

  7. 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.

  8. 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 ?
  9. 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.
  10. 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

  11. (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.

  12. 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?

  13. Everything = 42 by marcovje · · Score: 4, Funny


    Everything = 42 :-)

  14. 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 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.
    2. 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.

    3. 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. ;)

    4. 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=

    5. 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.

    6. 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.
    7. Re:Actually... by psbrogna · · Score: 5, Funny

      For example, MS Windows.

  15. 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.

  16. 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.
  17. 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.
  18. 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?
  19. 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
  20. 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.

  21. 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
  22. 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.

  23. 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.

  24. Comment removed by account_deleted · · Score: 4, Interesting

    Comment removed based on user account deletion

  25. 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."

  26. 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