∫ sin x cos 2x sin 3x dx
We know 2sinAcosB = sin(A + B) + sin(A – B)
∴ sin3xcos2x =
∴ The given equation becomes
⇒
⇒
We know 2sinAsinB = cos(A – B) – cos(A + B)
∴ sin5xsinx =
Also sin2x =
∴ Above equation can be written as
⇒
⇒
We know
⇒
⇒
⇒
NOTE: – Whenever you are solving integral questions having trigonometric functions in the product then the first thing that should be done is convert them in the form of addition or subtraction.