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prove that sin(2x).sin(x/2)-sin(3x).sin((9x)/2)= sin(5x).sin((5x)/2)
4 years ago

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oobleck
recall your product-to-sum formulas
sinAsinB = (cos(A-B) - cos(A+B))/2
do the conversions, and things will drop right out
4 years ago

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