3.2 Relations and Functions comp.notebook
September 23, 2016
3-2 Functions
Hours worked
0
1
2
3
Pay
$0
$4.25
$8.50
$12.75
You can write the data in the table as a set of ordered pairs.
{(0,0), (1,4.25),(2,8.5),(3,12.75)}
Any set of ordered pairs is called a relation.
A function is a relation that assigns exactly one value of the
dependent variable to each value of the independent variables.
We can create a mapping diagram for this data:Hours worked
Pay
We can create a graph for this data:-
The DOMAIN of a relation is the set of first coordinates, or
x-values, or independent variable, or input.
The RANGE of a relation is the set of second coordinates, or
y-values, or dependent variable, or output.
Aug 25­9:25 PM
3.2 Relations and Functions comp.notebook
Ex. 1 Is the following data a relation?
y
x
11
12
13
20
-2
-1
0
7
The domain is:
The range is:
Aug 25­9:32 PM
September 23, 2016
3.2 Relations and Functions comp.notebook
September 23, 2016
Ex. 4
Is the following relation a function?
x
y
-2
-3
6
-2
-1
0
3
1
This relation is NOT a function because two different y-values
are assigned to one x-value.
Ex. 5
Give the domain and range of the relation and
determine if the relation is a function?
{(-4,3), (1,0), (2, 3), (5,6)}
TRY
Give the domain and range of the relation and
determine if the relation is a function?
Aug 25­9:35 PM
3.2 Relations and Functions comp.notebook
September 23, 2016
Analyzing graphs
To determine if a relation is a function, we use the
vertical line test.
If a vertical line passes through the graph of a
function more than once, the graph is not the graph
of a function.
Aug 29­1:59 PM