∫sin2xsin5x.sin3xdx
sin2x=sin(5x−3x)
=sin5xcos3x−cot5xsin3x
sin2xsin5x.sin3x=sin5xcos3xsin5xsin3x−cos5xsin3xsin5xsin3x
=cot3x−cot5x
∫(cot3x−cot5x)dx
=∫cos3xdx−∫cot5xdx
=∫cot3xdx=∫cos3xsin3xdx=13log(sin3x)+C1
=∫cot5xdx=∫cos5xsin5xdx=15log(sin5x)+C2
∫(cot3x−cot5x)dx=13log(sin3x)−15log(sin5x)+C
∫sin2xsin5x.sin3xdx=13log(sin3x)−15log(sin5x)+C