SOLUTION: How do you rewrite the expression cos^2(2x) in terms of the first power of the cosine?

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Question 1004892: How do you rewrite the expression cos^2(2x) in terms of the first power of the cosine?
Answer by fractalier(6550) About Me  (Show Source):
You can put this solution on YOUR website!
Well cos(2x) = cos^2(x) - sin^2(x) = 2cos^2(x) - 1
and we will need to square that...so
cos^2(2x) = [2cos^2(x) - 1]^2 = 4cos^4(x) - 4cos^2(x) + 1