What is the integral of int sin^5 (x) dx?

1 Answer
Mar 4, 2018

The answer is =-1/5cos^5x+2/3cos^3x-cosx+C

Explanation:

We need

sin^2x+cos^2x=1

The integral is

intsin^5dx=int(1-cos^2x)^2sinxdx

Perform the substitution

u=cosx, =>, du=-sinxdx

Therefore,

intsin^5dx=-int(1-u^2)^2du

=-int(1-2u^2+u^4)du

=-intu^4du+2intu^2du-intdu

=-u^5/5+2u^3/3-u

=-1/5cos^5x+2/3cos^3x-cosx+C