Functions

A function from set X to set Y

A special relation that maps each element x in set X to only one element y in set Y

Vertical line test

Used to determine whether the given graph is a function or otherwise

Domain of a function

Set of possible values of x which defines a function

Range

Set of values of y that are obtained by substituting all the possible values of x

Product of combination of two functions that written as fg(x) or gf(x)

Process of combination by replacing two functions f and g to generate f[g(x)] or g[f(x)]

Inverse function

Reversal of a function such that every element in the codomain is mapped to only one element in the domain

Horizontal line test

Can be used to test the existence of inverse functions

f has inverse function

h does not have inverse function

If f and g are inverse functions of each other

-domain of f=range of g and domain of g=range of f -graph g is the reflection of graph f on the line y = x