Question

proving identities:
cos x (secx-cosx) = sin^2 x

Answer 1

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Answer 2

cos x(secx-cosx)=sin^2 x
cos x (1/cos x - cos x) = sin^2 x
cos x (1-cos^2 x / cos)=sin^2 x
then cancel cos x
1-cos^2 x = sin^ 2 x
sin^2 x = sin^2 x

Answer 3

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