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Diff eq question:

  1. Feb 8, 2009 #1
    1. The problem statement, all variables and given/known data
    dy/dx = (6x^2)/((1+x^3)y)


    2. Relevant equations



    3. The attempt at a solution

    it's a separable func. so after integrating, it looks like this (base on my calculation)

    y^2 = 36ln(1+x^3)

    so how do i find y? is it just sqrt(36ln(1+x^3))

    thanks
     
  2. jcsd
  3. Feb 8, 2009 #2

    Dick

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    36? Really? Could you check that again? Aside from that, sure, except y^2=A has two solutions. y=+sqrt(A) and y=-sqrt(A).
     
  4. Feb 8, 2009 #3
    is the 36 supposed to be a 4?

    brain fart... suddenly forgot how to do integration..
     
  5. Feb 8, 2009 #4

    Dick

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    Well, I got 4. Doesn't mean it's correct. If you're not sure you'd better check again.
     
  6. Feb 8, 2009 #5

    epenguin

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    I think it's 4 but also I think it's not going to matter too much when you get to the end. :wink:
     
  7. Feb 8, 2009 #6
    Thanks guys!

    i'm pretty sure (lol) it's 4
     
  8. Feb 9, 2009 #7

    epenguin

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    I suggest you also try writing it in the form x=
    and also express both forms in terms of an initial condition e.g. xy=0 and/or yx=0.
     
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