SOLUTION: cos sq 4 theta -sin sq 4 theta = -1

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Question 1103102: cos sq 4 theta -sin sq 4 theta = -1
Answer by greenestamps(13215) About Me  (Show Source):
You can put this solution on YOUR website!


cos^2(x)-sin^2(x) is the formula for cos(2x). So your equation

cos%284x%29%5E2-sin%284x%29%5E2+=+-1

is equivalent to

cos%288x%29+=+-1

8x+=+%28pi%29%2B2k%2Api
x+=+%28pi%29%2F8+%2B+%282k%2F8%29%2Api