Integrate cos^2A

Integrating sin^2A and cos^2A is a bit nasty so we can use double angle formula to make it a little simpler. cos2A = cos^2A - sin^2A = 2cos^2A - 1. We can rearrange to get cos^2A in nicer terms. cos^2A = 1/2(cos2A + 1)We can now integrate 1/2(cos2A + 1) as we would normally.1/4(sin2A+ 2A)