I have two problems I don't really know how to work through.
The first is the integral from 0 to 1 of r^3/(sqr(4+r^2))
I started by integrating by parts and eventually ended up with (4+r^2)^(7/2) so I know I'm doing something wrong.
The other problem is: find the integral of cosPIx * cos4PIx
I don't know where to begin here. Any help would be appreciated.