Thanks
IDK if this is the best way to get the answer, but it's how I found it. Fist, cos2x = cos^2x-sin^2x so
multiply by
Mess with the denominator:
And now we can use these rules:
Simplify
Simplify
Make substitution
Distribute the 2 into the denominator
Integrate
Anti-substitute
I'm pretty sure that's right, at the very least, I like all the steps I used to get there.