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Homework Help: Partial differential

  1. Jul 13, 2006 #1
    Hello, I'm new at these equations so I need help. I'm not able to solve this partial differential equation, if there is somebody who can help me do it plzz...

    http://galeb.etf.bg.ac.yu/~ii030168d/problem/problem.GIF [Broken]

    OK, it begins like this:

    http://galeb.etf.bg.ac.yu/~ii030168d/problem/problem1.GIF [Broken]

    But I don't know what to do next... This problem is from exam on my faculty. (I havent pass)


    I would appreciate any help...
     
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Jul 14, 2006 #2

    arildno

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    Well, the first equation may be rewrittent as a ratio between the differentials of x and y as follows:
    [tex]\frac{dy}{dx}=\frac{x-y-x^{2}y}{x+y+xy^{2}}[/tex]
    I'm not sure if this is analytically solvable, though..
     
  4. Jul 14, 2006 #3

    arildno

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    You MIGHT try changing of variables u=x+y, v=x-y; possibly, that will simplify the expressions.
     
  5. Jul 16, 2006 #4
    Sorry I made a mistake, problem is next:

    dx/(x+y-xy^2) = dy/(x^2y-x-y) = dz/(z(y^2-x^2))

    Maybe now there is solution. Those changes can't help, they wouldnt simplify the expression, but thanks...
     
    Last edited: Jul 16, 2006
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