1. The problem statement, all variables and given/known data I'm trying to simplify some trigonometric expressions, I'm attaching my work here. This comes from a famous physics problem i.e. the rod with two masses spinning on a circle. I've tried many times but I just can't get it. Any help on which identities to use would really help me. 2. Relevant equations I'm attaching the simplified version, the 'answer' 3. The attempt at a solution I'm attaching my work.