# Evaluate integral of sec(4x) with respect to x

Let . Then , so . Rewrite using and .
Let . Find .
Rewrite.
Divide by .
Rewrite the problem using and .
Combine and .
Since is constant with respect to , move out of the integral.
The integral of with respect to is .
Simplify.
Simplify.
Combine and .
Replace all occurrences of with .
Evaluate integral of sec(4x) with respect to x