Recall the following definitions: [br][br][b]A relation is a correspondence between 2 sets. [br]Algebraically, you can think of a relation as a set of ordered pairs (x,y). [/b][br][br][color=#0000ff][b]Once special type of relation is called a FUNCTION.[/b][/color] [br][color=#0000ff][b]Every function is a relation,[/b][/color] [color=#cc0000][b]but not every relation is a function. [br] [br][/b][/color][color=#0000ff][b]A function is a relation for which each and every input gets mapped to ONE and ONLY ONE output.[/b][br][/color]The following applets help further illustrate this concept for functions represented graphically. [br]