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

1 Answer
Nov 21, 2015

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

Explanation:

We have

intsin(x)tan(x)dxsin(x)tan(x)dx

Or, in other terms

intsin^2(x)/cos(x)dxsin2(x)cos(x)dx

Or, since sin^2(x) = 1 - cos^2(x)sin2(x)=1cos2(x)

int(1 - cos^2(x))/cos(x)dx1cos2(x)cos(x)dx

Doing the fraction we have

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

Break the integral into fractions

intsec(x)dx - intcos(x)dxsec(x)dxcos(x)dx

And those are standard integrals, so evaluate that

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