Question

integration of sin3xcosx​

Answer 1

sin3x = 3sinx -4sin³x

now

sin3xcosx = int(3sinx-4sin³x)cosdx

let sinx=t

cosxdx =dt

int(3t-4t³)dt

3t²/2 -4t⁴/4

3t²/2 -t⁴

3sin²x /2 -sin⁴x