A relation is any set of ordered pairs.

1
A relation is any set of ordered pairs.
Ex. ( 2, -3) (4, 5) (-1, 7) (4, 3) (0, 5)
The first part of each of the ordered pairs (the
x part) is called the domain. The second part of
each of the ordered pairs ( the y part) is called
the range.
Domain 2 4 -1 0
Range -3 5 7 3
A relation may be expressed as a listing of the
ordered pairs, as an equation, with words, or
with a graph.
2
A function is a special kind of relation where
each x in the domain is paired with exactly one y
in the range.
set of ordered pairs equation descriptive
words graph
input
output
3
Suppose our rule is double the number
As an equation
As a set of ordered pairs
As a graph
4
Determining if a relation is a
function. Remember that a function has only one
output value for each input value. ( each x is
paired with exactly one y)
Ex. ( 2, -3) (4, 5) (-1, 7) (4, 3) (0, 5)
Not a function. Four has two outputs, 5 and 3.
If the relation is given in the form of an
equation, solve for y. If there is only one
answer, then the relation is a function.
If the relation is given by a graph, use the
vertical line test.
5
Solve the following equations for y.
6
Evaluating Functions for Given Values
Homework- Practice 20 p. 149-150 1-37 odds,
55-63 odds