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tammyhawatmeh
sin 2θ cos θ − cos 2θ sin θ =root2/2
the right side becomes sin θ by the difference identity for sine so θ = pi/4 or 3pi/4.
sin 2x = 2sinx cosx cos 2x = 2cos^2 -1 --> 2sinx cos^2 -2sinx cos^2 + sinx = root2/2