Whitman College: David Guichard's "Calculus, Chapter 3: Rules for Finding Derivatives, Section 3.5: The Chain Rule"
Read Section 3.5 (pages 65-69). The chain rule explains how the derivative applies to the composition of functions. Pay particular attention to Example 3.11, as it works through a derivative computation where all of the differentiation rules of this unit are applied in finding the derivative of one function.