Chapter 3
Section 3.1
Objectives:
•Identify Ordered Pair
•Identify a Relation
•Identify the Domain and Range of a Relation
Ordered Pair
Ordered Pair: Given two related elements x and y. An
ordered pair that represent x and y can be written as ( x, y ).
Example 1: ( 5, 3 ) is an ordered pair
Example 2: ( Asma, 10) is also an ordered pair.
Notes:
1.
( 5, 3 ) and ( 3, 5 ) are two different pairs
2.
{ 5 , 3 } is not an ordered pair
3.
5, 3 cannot be an ordered pair
Class Exercise 1
Which of the following is an ordered pair
a) { ½ , -3 }
b) ( -3, ½ )
d) ( 1 , - 5 )
e) -3, 6
Answer:
b and d
c) { ( 5, 0 ) }
Relation
Relation A set of ordered pairs is a relation
Example 1:
 Ahmad,5, Saeed ,  5, Rashid ,100, Obaid ,25 
is a relation.
Domain
Domain:
The set of all first elements in a relation is called the domain of the relation
Example 1: Find the domain of each relation
a ) A   Ahmad , 58, Rashid ,32 , Michael ,29 
Domain of A = { Ahmad, Rashid, Michael }


1
b) B   5, ,  4,5,  12,0 ,  16,  
2


Domain of B = { 5, -4, -12, -16 }
Range
Range: The set of all second elements in a relation is called the range
of the relation
Example 1: Find the range of each relation
a ) A   Ahmad , 58, Rashid ,32 , Michael ,29 
Range of A  58, 32, 29


1
b) B   5, ,  4,5,  12,0 ,  16,  
2


1

Range of B   ,  5, 0,  
2

Class Exercise 2
Find the domain and range of each relation
a ) Abu Dhabi , 1, Dubai , 2 , Sharjah, 3, RAK , 3, Fujairah, 2 
b) A  1, Ahmad ,  2, Ahmad , 3, Ahmad 
Answers :
a ) Domain  Abu Dhabi , Dubai , Sharjah, Fujairah
Range
 1, 2, 3, 
b) Domain of A  1,  2, 3
Range of A  Ahmad 
Home Work
• Do All Assigned Home Work in the
Syllabus