# Evaluate integral of cos(x)^2 with respect to x

Evaluate integral of cos(x)^2 with respect to x
Use the half-angle formula to rewrite as .
Since is constant with respect to , move out of the integral.
Split the single integral into multiple integrals.
Since is constant with respect to , move out of the integral.
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.
Replace all occurrences of with .