1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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


    User Avatar
    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:
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook