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Homework Help: Two ODE's I don't know how to start

  1. Apr 6, 2009 #1
    Hey all,

    I have these 2 ODE's that I have to solve:

    [tex]a.) y' = ay - by^{3} ; a,b > 0

    [tex]b.) y' = (a cos(x) + b)y - y^{3}[/tex]

    I'm not even exactly sure what method to use for these...

    I tried splitting up the variables in a.) but it got kinda messy:

    [tex] \int \frac{dy}{y(a-by^{2})} = \int dx [/tex]

    Is there a better way to approach it?
    A method suggestion for b.) would be great!
  2. jcsd
  3. Apr 6, 2009 #2


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    Science Advisor
    Homework Helper

    Hi Damascus Road! :smile:

    For a.) use partial fractions on 1/y(a-by2) :wink:

    For b.) … I've no idea :redface:
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