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    x*dy/dx - y = x^2 * e^x
    y=2 when x=1

    been struggling with this for a while now
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    use an integrating factor
    firstly divide throughout by x giving you,

    dy/dx - (1/x)y = xe^x

    and go from there by finding the integrating factor and so on, which im assuming youll know about, but if you dont i can help.
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    what's an integrating factor?
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    What do you want to do with the equation?

    Unless you've done D.E as a module, I can't see anyway of solving this equation except for substituting your conditions x=1 when y=2 into the equation and solving from there.
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    what module are you doing? you might not even need to know how to do this, unless your doing DE (MEI) or some FP2/3 modules
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    i don't think i have been taught how to do it

    is the integrating factor dx? i tried multiplying through by dx then integrating both sides, getting:
    y=xe^x-e^x/1-lnx

    this looks different to the answer in my book, so i'm guessing i've gone wrong
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    (Original post by schoolstudent)
    i don't think i have been taught how to do it

    is the integrating factor dx? i tried multiplying through by dx then integrating both sides, getting:
    y=xe^x-e^x/1-lnx

    this looks different to the answer in my book, so i'm guessing i've gone wrong
    hope it helps (:

    btw, ignore the line "which simply equals x"
    Attached Images
  1. File Type: pdf Integrating factor.pdf (386.5 KB, 49 views)
 
 
 
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Updated: January 13, 2010
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