Home MATHEMATICS TOPIC 2: FUNCTIONS ~ MATHEMATICS FORM 3

# TOPIC 2: FUNCTIONS ~ MATHEMATICS FORM 3

2025
77 ### TOPIC 2: FUNCTIONS ~ MATHEMATICS FORM 3

Normally relation deals with matching of elements from the first set called

DOMAIN with the element of the second set called RANGE.
Definitions:
A
function is a relation with a property that for each element in the
domain there is only one corresponding element in the range or co-
domain
Therefore functions are relations but not all relations are functions
The Concept of a Functions Pictorially
Explain the concept of a functions pictorially
Example 1
Which of the following relation are functions?  Solution
1. It is not a function since 3 and 6 remain unmapped.
2. It is not a function because 2 has two images ( 5 and 6)
3. It is a function because each of 1, 2, 3 and 4 is connected to exactly one of 5, 6 or 7.
Functions
Identify functions
TESTING FOR FUNCTIONS;
If
a line parallel to the y-axis is drawn and it passes through two or
more points on the graph of the relation then the relation is not a
function.
If it passes through only one point then the relation is a function
Example 2
Identify each of the following graphs as functions or not.      Exercise 1
1. Which of the following relations are functions? 2. Let A = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
and B ={ 2, 3, 5, 7 }
Draw an arrow diagram to illustrate the relation “ is a multiple of ‘ is it a function ? why?
3. let A = {1,-1 ,2,-2} and
B = {1, 2, 3, 4 } which of the following relations are functions ?
1. { ( x , y ) : x < y }
2. { ( x , y ) : x > y}
3. { ( x , y ) : y = x2}

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