I'm having a bit of trouble integrating:

$\displaystyle \int(sin(2x) + cos(2x))^2 \ dx$. According to the solution in the back of my book, it's supposed to be $\displaystyle x - (1/4)cos(4x) + C$.

I was thinking of using integration by parts with my $\displaystyle dv = (sin(2x) + cos(2x))$. Anybody have any ideas on how to solve this?