Trigonometric Properties (III)

Double-Argument Properties: sin 2x = 2 sinx cosx cos 2x = cos2x - sin2x = 1 - 2 sin2x = 2 cos2x - 1

Half-Argument Properties:

Sum and Product Properties: 2 cos A cos B = cos(A + B) + cos(A - B) 2 sin A sin B = -cos(A + B) + cos(A -B) 2 sin A cos B = sin(A + B) + sin(A -B) 2 cos A sin B = sin(A + B) - sin (A -B)

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