Slashdot Mirror


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?"

19 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. 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.

  3. (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.

  4. 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
  5. 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 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.

    4. 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).

  6. 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.
  7. 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.
  8. 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.

  9. 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.

  10. 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?
  11. 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.

  12. 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)

  13. 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.)

  14. 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