Integrate Cos^2(x)

{} = integral sign for purpose of this solutioncos2x = 1 - sin2x (1)cos 2x = cos2x - sin2x (2)cos2x = 1 - (cos2x - cos 2x)cos2x = 1 - cos2x + cos 2x2 cos2x = 1 + cos 2xcos2x = (1 + cos 2x)/2{} cos2(x) dx = {} (cos (2x) +1)/2 dx . = 1/2 {} 1 dx + 1/2 {} cos (2x) dx = 1/2 x + (sin 2x)/4 + C

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