1. ## Improper Integral

The integral from negative infinity to positive infinite: x^2 / (9+x^6) dx

I've broken it up into the sum of two integrals (one from neg. infinity to zero, and the other from zero to pos. infinity) but I'm stuck at this point.

Thanks for any help!

2. Have you considered the substitution $u\;=\;x^{3}$?

3. After splitting it up, did you actually evaluate both integrals or did you notice the symmetry and cut your work in half?