trig

Prove that sin squared 20 degrees+sin squared 40 degrees+ sin squared 80 degrees is equal to 3/2

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  1. sin^2(20) = 0.116,997,778.
    sin^2(40) = 0.413,175,911.
    sin^2(80) = 0.969,846,310.

    Sum = 1.500 = 1 1/2 = 3/2.

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