### Home > CALC > Chapter 11 > Lesson 11.3.1 > Problem 11-97

11-97.

The Reverse Chain Rule can be used here, but this is an improper integral, so be sure to use a limit.

Let *u* = tan(*x*).

Use partial fraction decomposition.

Use substitution twice.

Let *u* = *x*^{2}. Then *du* = 2*x*.

Let *v* = cos(*u*). Then *dv* = –sin(*u*)*du*.