Texas Instruments
Texas Instruments: Relations and Functions
A function is a relation that assigns exactly one value of the dependent variable to each value of the independent variable. When a function is graphed, a vertical line can pass through the graph and touch only one point.
Math Is Fun
Math Is Fun: What Is a Function
The learning resource investigates functions. Students learn about the concept by exploring definitions and examples. Topics include the vertical line test, relations, and ordered pairs.
Richland Community College
Richland Community College: Graphs of Functions
This site from the Richland Community College provides graphs of Functions offers loose definitions of many terms relative to the graphing of functions.