Hi,
I'm trying to solve the following integral:

I'm under the impression it can be solved as an elliptical integral, but I'm unsure how I would get it into such a form. I've tried applying the sum-difference formula to the cosines, but I didn't find that helpful either. Any help that can be offered is appreciated; I need to understand the steps involved in solving it, so simply pushing it into Wolfram and getting an answer is not going to help me. Thanks in advance.
I'm trying to solve the following integral:
I'm under the impression it can be solved as an elliptical integral, but I'm unsure how I would get it into such a form. I've tried applying the sum-difference formula to the cosines, but I didn't find that helpful either. Any help that can be offered is appreciated; I need to understand the steps involved in solving it, so simply pushing it into Wolfram and getting an answer is not going to help me. Thanks in advance.