# Math Help - strange double integral

1. ## strange double integral

Don't have idea what to do with this...

I(- to + infiniti) I(- to + infiniti) (x2+y2)e to the power of(-x4 -(2x2) * y2 -y4) dy dx

So it is a double integral...

2. Originally Posted by fiksi
Don't have idea what to do with this...

I(- to + infiniti) I(- to + infiniti) (x2+y2)e to the power of(-x4 -(2x2) * y2 -y4) dy dx

So it is a double integral...
Switching to polar coords
$\int_{-\infty}^\infty \int_{-\infty}^\infty (x^2+y^2) e^{-x^4-2 x^2 y^2-y^4}\,dx \,dy = \int_0^{2\pi} \int_0^\infty r^3 e^{-r^4}\, dr\, d \theta$ which I believe is integrable.