Pre-Cal 20S January 12, 2009

This document discusses functions and relations. It defines a function as a special type of relation where each input is mapped to exactly one output. Not all relations are functions. The domain of a function is the set of all possible inputs, and the range is the set of all possible outputs. A relation is a function if the vertical line test is passed - meaning a vertical line cannot cross the graph in more than one place. Examples of functions and non-functions are provided to illustrate these concepts.