Function: contains a rule of correspondence that assigns to each element of the domain (x) and exactly one corresponding element in the range (y)

***Common Functions:
                     constant: y=1
                     identity: y=x
                     absolute value: y=|x|
                    

Graph: a collection of ordered pairs (x,f(x)) such that x is a domain of f

Inverse: occurs when a functions domain and range (x and y) are reversed
            ***is a function if the inverse passes the horizontal line test

Composition: process of making a composite function of two functions
            *** (f o g)(x)= f(g(x))
            *** (g o f)(x)= g(f(x))