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Cos^4A - Cos^2 = sin^4 - sin^2A |
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Answer» Thanks brother Cos ^4 A - cos ^2 A = (cos^2 A)^2 - cos^2 A = cos^2 A (cos ^2 A - 1) = - cos^2 A(1-cos^2A) =- cos^2 A * sin^2 A =- (1- sin^2 A)*sin^2 A = (sin^2 A - 1)*sin^2 A = sin^4 A - sin^2 AHence, proved |
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