Basically, I've been banging my head for ages about this integral $$\int \frac{x^2}{\cos(x) + \sin(x)}\,dx$$
I've tried to simplify it to$$ \frac{1}{\sqrt2} \int x^2\sec(x-(\pi/4))\,dx$$ But that's when it got especially difficult.
Any ideas on how to solve it without using the WRA?