How do you find the antiderivative of int tan^3xsecx dxtan3xsecxdx?

1 Answer
Feb 2, 2017

inttan^3xsecxdx=1/3sec^3x-secx+Ctan3xsecxdx=13sec3xsecx+C

Explanation:

I=inttan^3xsecxdxI=tan3xsecxdx

Rewrite this using tan^2x+1=sec^2xtan2x+1=sec2x:

I=inttan^2xtanxsecxdxI=tan2xtanxsecxdx

I=int(sec^2x-1)(secxtanx)dxI=(sec2x1)(secxtanx)dx

Let u=secxu=secx. Then du=secxtanxdxdu=secxtanxdx:

I=int(u^2-1)duI=(u21)du

I=1/3u^3-u+CI=13u3u+C

I=1/3sec^3x-secx+CI=13sec3xsecx+C