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# differential equation watch

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

been struggling with this for a while now
2. 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.
3. what's an integrating factor?
4. 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.
5. 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
6. 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
7. (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
8. Integrating factor.pdf (386.5 KB, 49 views)

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