1. The problem statement, all variables and given/known data Determine the power generated by a voltage V = 240∠15° volts driving a current I = 12 ∠75° 2. Relevant equations P=VIcos(ø-ø) 3. The attempt at a solution This is a worked example from my open university course. The answer is 240x12cos(15°-75°) = 1440W. I can not for the life in me work out how they have arrived at this answer. I get cos-60= 0.58. then times 240x12= 1692.9 W. Must be doing something wrong!