∫dxsin x.sin(x+α) is equal to
cosec α log∣∣sin xsin(x+α)∣∣+C
∫dxsin x.sin(x+α)=1sinα∫sin((x+α)−x)sin x.sin(x+α)dx=cosec α∫(sin(x+α)cos x−cos(x+α)sin x)sin x.sin(x+α)dx=cosec α∫[cot x−cot(x+α)]dx=cosec α[log sin x−log sin(x+α)]+C=cosec α log∣∣sin xsin(x+α)∣∣+C