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**stuckbigtime** Question is v=240sin(100 pi t-pi/6) i=30cos(100 pi t+pi/3)

power = V x i

find max power and time it first occurs

I have expanded v to give me (207.84sin 100 pi t-120 cos 100 pi t)

and expanded i to give me (15 cos 100 pi t - 25.98 sin 100 pi t)

multiply v x i gives me

3117.6 sin 100 pi t cos 100 pi t - 5399.68sinē 100 pi t - 1800 cosē 100 pi t + 3117.6 cos 100 pi t sin 100 pi t

not too sure if I have my + and - in correct places after I have multiplied and i'm stuck after that about how to get my max power and time answers ??

any help would be greatful its quite a big question