SOLUTION: Use a double-angle identity to find the exact value of the expression: {{{1 - 2sin^2(75)}}}

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Question 1115146: Use a double-angle identity to find the exact value of the expression:
1+-+2sin%5E2%2875%29
Answer by ikleyn(52847) About Me  (Show Source):
You can put this solution on YOUR website!
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1+-+2sin%5E2%2875%5Eo%29 = cos(2*75°) = cos(150°) = -sqrt%283%29%2F2.