Examples of Math Problems: prove this equation to be an identity; (sin(3x/7))(cos(4x/7)) + (cos(3x/7))(sin(4x/7)) = sin(x)

Monday, June 10, 2013

prove this equation to be an identity; (sin(3x/7))(cos(4x/7)) + (cos(3x/7))(sin(4x/7)) = sin(x)

Angle sum formula:
%0D%0Asin%28x%2By%29=sin%28x%29cos%28y%29-cos%28x%29sin%28y%29%0D%0A

%0D%0Asin%28x%2By%29=sin%28x%29cos%28y%29-cos%28x%29sin%28y%29%0D%0A

the two angles are 3x/7 and 4x/7

therefore their sum is x

:)

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