What's the integral of #int sin(x)tan(x) dx#?

1 Answer
Nov 21, 2015

#intsin(x)tan(x)dx = ln|sec(x) + tan(x)| - sin(x) + c#

Explanation:

We have

#intsin(x)tan(x)dx#

Or, in other terms

#intsin^2(x)/cos(x)dx#

Or, since #sin^2(x) = 1 - cos^2(x)#

#int(1 - cos^2(x))/cos(x)dx#

Doing the fraction we have

#int(sec(x) - cos(x))dx#

Break the integral into fractions

#intsec(x)dx - intcos(x)dx#

And those are standard integrals, so evaluate that

#intsin(x)tan(x)dx = ln|sec(x) + tan(x)| - sin(x) + c#