### Home > CALC > Chapter 9 > Lesson 9.2.2 > Problem 9-64

9-64.

Examine the integrals below. Consider the multiple tools available for integrating and use the best strategy. After evaluating each integral, write a short description of your method. Homework Help ✎

Use substitution: Let *u* = *x*^{2} + 1

cos(4*θ*) = cos(2(2*θ*)) = 2(cos^{2}(2*θ*)) − 1

Substitute using the hint, then integrate using substitution.

Let *u* = cos(2*θ*).

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

Use substitution: Let *u* = *x*^{4}