1. The problem statement, all variables and given/known data 8sin(200t) - 6 cos(200t - pi/4) 2. Relevant equations 3. The attempt at a solution I'm trying to calculate the average power for that expression so: I need to get that expression into either one term with the same frequency and phase angle or two terms with a different frequency. I've tried a bunch of different methods but can't quite get anything.. I've tried to turn 8sin(200t) into 4cos(100t)sin(100t) = 4cos(100t)cos(100t - pi/2) but then I get stuck with cosines multiplying each other. Any help?