Functions

A function is a set of ordered pairs in which no two ordered pairs have the same first values

this can be determined by a vertical line test.

Domain is the "first value"

The range is the plug in of the first value being evaluated by the function

Notation

y=f(x)

f(x)=2x+1

f(1)=2+1= 3

ordered pair is then (1,3)


1 to 1 function No two ordered pairs have the same 2nd value or range?

this can be determined by a horizontal line test.

if always increasing or decreasing a function satisfies the 1 to 1 definition of a function