Originally Posted by

**DarrenM** I'm a bit stuck on these. A nudge in the right direction would be much appreciated.

$\displaystyle \int_{- \frac {\pi}{2}}^{\frac {\pi}{2}} \frac {x^{2} sin{x}}{1+x^{6}} dx

$

I can't seem to figure out what to do with that sin(x) function. If I let $\displaystyle u = x^{3}$, I can get the whole thing into the form of the derivative of arctan(x), except for the sin(x).

The other one that's bugging me is:

$\displaystyle \int_{0}^{4} \frac {x}{\sqrt{1+2x}} dx$

No excuse here. I've tried quite a few different substitutions and algebraic manipulations without success. I can't shake the feeling that I'm over-looking something glaring with this problem. I think I found a method that would involve using partial fractions, but I was told that none of these problems required that method.