1. Joined
    08 Oct '06
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    24000
    27 Feb '10 19:40
    Do you guys have a favorite equation?

    Mine is e^(i*pi)+1=0.
  2. Germany
    Joined
    27 Oct '08
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    3085
    27 Feb '10 20:23
    At the moment, the Gross-Pitaevskii-equation.
  3. Joined
    07 Sep '05
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    35068
    28 Feb '10 11:441 edit
    Originally posted by amolv06
    Mine is e^(i*pi)+1=0.
    That is a nice one, though you could argue it's an identity rather than an equation. If you wanted to be picky. 🙂
  4. SubscriberAThousandYoung
    West Coast Rioter
    tinyurl.com/y7loem9q
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    28 Feb '10 12:31
    F = M/2 +7

    A formula for determining how young you should date. If you're 30, then 1/2 of that is 15, +7 is 22. Avoid the 21 and under crowd.
  5. Cape Town
    Joined
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    52945
    28 Feb '10 14:59
    Originally posted by AThousandYoung
    F = M/2 +7

    A formula for determining how young you should date. If you're 30, then 1/2 of that is 15, +7 is 22. Avoid the 21 and under crowd.
    Neither my father nor sister followed that equation, and so far have had quite successful marriages.
  6. SubscriberAThousandYoung
    West Coast Rioter
    tinyurl.com/y7loem9q
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    28 Feb '10 15:51
    Originally posted by twhitehead
    Neither my father nor sister followed that equation, and so far have had quite successful marriages.
    What were your parents' ages when they started dating?
  7. Joined
    11 Nov '05
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    43938
    01 Mar '10 08:101 edit
    One of the most interesting equations, and one of the most famous ones too, I believe, is this:
    a^n + b^n = c^n, where a,b,c is an integer >0 and n is an integer >2.
    Fermat got interested in it, and myriads of mathematicians thereafter.

    One of the matematicians working with this equation is Sophie Germain (1776 - 1831) who has one of the most interesting life stories. She was a lady matematician in the area no women worked before. There is even a set of integers that is named after her.

    The problem is now solved: There are no a,b,c, and n that can solve the equation. This is not interesting. What's interesting IMHO is that a seemingly simple equation is so difficult to deal with. Not many mathematicians can understand the proof. But in its simpler form it is understandable for amateur mathematicians. Like the case n=4 and some more.

    Simon Sing brought the attention to this equation in his book "Femat's Last Theroem".
  8. Cape Town
    Joined
    14 Apr '05
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    01 Mar '10 08:28
    Originally posted by AThousandYoung
    What were your parents' ages when they started dating?
    I don't know exactly but about 41 and 21.
  9. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
    Joined
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    01 Mar '10 12:53
    One of my favorites: B4IFQ(RU/18)
  10. silicon valley
    Joined
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    01 Mar '10 17:47
    http://en.wikipedia.org/wiki/Maxwell%27s_equations#General_formulation
  11. Joined
    01 Jan '09
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    63
    01 Mar '10 23:28
    Originally posted by mtthw
    That is a nice one, though you could argue it's an identity rather than an equation. If you wanted to be picky. 🙂
    An identity of what?
  12. Subscriberjoe shmo
    Strange Egg
    podunk, PA
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    02 Mar '10 02:551 edit
    Originally posted by talvtal
    An identity of what?
    A mathematical identity is one that remains constant regardless of the values of the variables in it.

    ex.

    (sin(A))^2 + (cos(A))^2 = 1

    no matter what value you substitue for "A" the equation is true.

    although now I'm slightly confused because there are no variables in e^(pi*i) = -1

    ?

    Edit: ok actually its just a special case (x=pi) of

    e^(ix) = cos(x) + i*sin(x)
  13. Subscriberjoe shmo
    Strange Egg
    podunk, PA
    Joined
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    02 Mar '10 03:21
    Originally posted by joe shmo
    A mathematical identity is one that remains constant regardless of the values of the variables in it.

    ex.

    (sin(A))^2 + (cos(A))^2 = 1

    no matter what value you substitue for "A" the equation is true.

    although now I'm slightly confused because there are no variables in e^(pi*i) = -1

    ?

    Edit: ok actually its just a special case (x=pi) of

    e^(ix) = cos(x) + i*sin(x)
    And while im at it

    I don't have a favorite yet, but one i'm currently looking at

    y" + (k^2)y = 0

    its soluion relates to Eulers identity.
  14. Cape Town
    Joined
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    52945
    02 Mar '10 05:32
    Originally posted by joe shmo
    A mathematical identity is one that remains constant regardless of the values of the variables in it.
    Don't all equations have that property?
  15. Joined
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    35068
    02 Mar '10 09:52
    Originally posted by twhitehead
    Don't all equations have that property?
    Contrasting with an equation, which is true for particular values. A simple example:

    2x = x + x, is an identity
    2x = x + 1, is an equation with the solution x = 1.
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