I'm having a bit of trouble with trying to prove LHS = RHS (or the other way around for that matter)
I have simplified the LHS to be 2/1-2cosxsinx but how do i get the RHS?
1) Do you know the sum-to-product rule?? If not better refer: Sum-to-Product formulas (Proof of these formulas could be found in many basic trignometric books.)
Does this solve your problems?? If not please don't hesitate to reply.