# Integration by Substitution

In this section, you will study techniques for integrating composite functions. The discussion is split into two partsâ€”pattern recognition and change of variables. Both techniques involve a u-substitution. With pattern recognition, you perform the substitution mentally, and with change of variables you write the substitution steps.

The role of substitution in integration is comparable to the role of the Chain Rule in differentiation.

## Essential Questions

Essential Questions

### How are indefinite integrals evaluated using substitution?

How are indefinite integrals evaluated using substitution?