What is the integral of int sec^3(x)dx?

1 Answer
Aug 2, 2018

I=1/2[secxtanx+ln|secx+tanx|]+C

Explanation:

Here,

I=intsec^3xdx.....to(A)

I=intsecx(sec^2x)dx

Using Integration by parts:

I=secx color(blue)(intsec^2xdx)-int(secxtanxcolor(blue)( intsec^2xdx))dx

I=secx*color(blue)(tanx)-intsecxtanx*color(blue)(tanx)dx

I=secxtanx-intsecxtan^2xdx

I=secxtanx-intsecx(sec^2x-1)dx

I=secxtanx-intsec^3xdx+intsecxdx

I=secxtanx-I+color(red)(intsecxdx)....to[use,eqn.(A)]

I+I=secxtanx+color(red)(ln|secx+tanx|)+c

2I=secxtanx+ln|secx+tanx|+c

I=1/2[secxtanx+ln|secx+tanx|]+c/2

I=1/2[secxtanx+ln|secx+tanx|]+C ,where, C=c/2