1. The problem statement, all variables and given/known data (1) (1+cosx)/(sinx)= cot (x/2) (2) 2 csc 2x= sec x csc x (3) cos^6 x- sin^6 x= cos 2x(1 - 1/4sin^2 2x) ( I think this has to do something with subtracting -3a^2b^2, since I need to get a-2ab+b to factor it..?) 2. Relevant equations Addition and Subtraction formulas (sin,cos and tan) Double angle formulas (Sin 2x, cos 2x (3 formulas), tan 2x) Reciprocal id., quotient id., Pythagorean Id. 3. The attempt at a solution Could someone explain the thought process of proving these identities, I have zillion more of these, and I think I am missing something. I think it is the double angle formulas that are confusing me. Thank you.