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Math Help - Difficult first order D.E

  1. #1
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    Difficult first order D.E

    I'm trying to solve dy/dx = (-y+xy) / (x-xy) using a change of variables but can't seem to find a substitution that works. Since the equation isn't homogenous u=y/x won't work. I've tried u=xy, u=-y+xy and u=x-xy all to no avail! Does anyone have a suggestion?

    Many Thanks
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  2. #2
    A Plied Mathematician
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    It's separable.
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  3. #3
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    Quote Originally Posted by Ackbeet View Post
    It's separable.
    How can it be separable when x and y appear in both the numerator and denominator? :S

    Edit: I now realise all I have to do is factorise top and bottom. I should have spotted this!
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  4. #4
    A Plied Mathematician
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    Right. There you go.
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