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Thread: find u'(x)

  1. #1
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    find u'(x)

    so i have the function: Y^'+ P(x)y=Q(x) where u(x) is the integrating factor, find u'(x).

    i have an answer i wanted to know if its right? i dont know why but i can attach my pdf file, anyways my answer is u'(x) = P(x)u(x)....is this right? thanks in advance..
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  2. #2
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    Quote Originally Posted by slapmaxwell1 View Post
    so i have the function: Y^'+ P(x)y=Q(x) where u(x) is the integrating factor, find u'(x).

    i have an answer i wanted to know if its right? i dont know why but i can attach my pdf file, anyways my answer is u'(x) = P(x)u(x)....is this right? thanks in advance..
    When you multiply through by u(x) the left hand side will be the derivative of u(x)y(x), that is:

    \frac{d}{dx}\left[u(x)y(x)\right]  = u(x)y'(x)+u'(x)y(x)= u(x)y'(x)+u(u)P(x)y(x)=u(x)Q(x)

    So u'(x)=P(x)u(x)

    CB
    Last edited by CaptainBlack; Feb 3rd 2010 at 04:27 AM.
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  3. #3
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    awesome i actually did it right! wait til my teacher finds out, im not retarded LOL
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