This document discusses functions and graphs. It defines a function as a relation where each element in the domain corresponds to exactly one element in the range. Examples are provided to demonstrate determining if a relation represents a function. Function notation is introduced along with using a graphing calculator to evaluate functions. The vertical line test is described as a way to identify graphs that represent functions based on y being a function of x. Methods are provided for obtaining information from graphs like identifying the domain and range and finding intercepts.