CPM Homework Banner
9-64.

Use substitution: Let u = x2 + 1

cos(4θ) = cos(2(2θ)) = 2(cos2(2θ)) − 1

Substitute using the hint, then integrate using substitution.
Let u = cos(2θ).

The integrand is a multiple of an inverse trigonometric function derivative.

Use substitution: Let u = x4