# Double integral problem

• Oct 2nd 2011, 02:47 PM
weber
Double 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 PM
TheEmptySet
Re: Double integral problem
Quote:

Originally Posted by weber
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!

I am going to guess that there is a typo in your problem. You state you don't know how to integrage

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

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

My guess is you mean this integral

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

If that is the case you need to use a substition

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

$\frac{1}{2}\iint u \, du \, dx$