1
MA 15200
Lesson 20
Section 2.1
A relation
is any set of ordered pairs.
The set of all first components of the ordered pairs
is called the
domain
.
The set of all second components is called the
range.
Relations can be represented by tables, sets, equations of two variables, or graphs.
Name
% of all Names
Smith
1.006%
Johnson
0.810%
Williams
0.699%
Brown
0.621%
Jones
0.621%
Ex 1:
Find the domain and range of each relation.
a)
{(2,
3),(3,
4),(4,
5),(5,
5),(2,
6)}





A relation in which each member of the domain corresponds to exactly one member of
the range is a
function
.
The table above that pairs a last name with a percent of all names
is a function because each last name is paired to exactly one percent.
Another way to
identify a function is the following, it is a
relation in which no two ordered pairs have
the same first component and different second components.
Definition of a Function
A
function
is a correspondence from a first set, called the
domain
, to a second set, called
the
range
, such that each element in the domain corresponds to
exactly one
element in
the range.
If the table was changed as below, the relation is not a function.
The percent 0.621%
would be paired with both Brown and Jones.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Fall '09
 Equations, Sets, line graph

Click to edit the document details