Dear MHF users!

I'm having problems with this integral:

http://www4b.wolframalpha.com/Calcul...=24&w=116&h=34

because in the first step, i dont know how to integrate this part: http://www4c.wolframalpha.com/Calcul...s=55&w=30&h=22

Thanks a lot!

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- Oct 2nd 2011, 02:47 PMweberDouble integral problem
Dear MHF users!

I'm having problems with this integral:

http://www4b.wolframalpha.com/Calcul...=24&w=116&h=34

because in the first step, i dont know how to integrate this part: http://www4c.wolframalpha.com/Calcul...s=55&w=30&h=22

Thanks a lot! - Oct 2nd 2011, 03:13 PMTheEmptySetRe: Double integral problem
I am going to guess that there is a typo in your problem. You state you don't know how to integrage

$\displaystyle \iint xy^{xy^2}\, dy \, dx$

but then you say you don't know how to integrate $\displaystyle e^{x^2y}$

My guess is you mean this integral

$\displaystyle \iint xye^{xy^2}\, dy \, dx$

If that is the case you need to use a substition

$\displaystyle u=e^{xy^2} \implies du=2xye^{xy^2}dy \iff \frac{du}{2}=xye^{xy^2}dy$

Now your integral is

$\displaystyle \frac{1}{2}\iint u \, du \, dx$ - Oct 2nd 2011, 03:15 PMweberRe: Double integral problem
OMG! you are 100% right!

Sorry for my typo =/

That's exactly what i wanted.

TheEmptySet, you are awesome! (: