Definition of a Function

1. GENERAL
MATHEMATICS

2.  Have you been in a
relationship or have you
felt like you were in a
special relationship with
someone?
RELATIONSHIP RULES
 What kind of
relationship was it?
 Where there rules?
 What were the rules?
numbers
MATH

3. VENDING MACHINES

4. VENDING MACHINES
Number
of coins
Cups of
RULE: For every
“5 peso coin”
comes one and
only one
cup of coffee.
=

5. VENDING MACHINES
INPUT
OUTPUT
RULE
RULE: For every
“5 peso coin”
comes one and
only one
cup of coffee.
RULE: For every
input there comes
one and only one
output

6. FUNCTIONS
A rule that says for every
input there is one and only
one output.

7. FUNCTION MACHINE
Input
Output
Rule
2 x
3
6
Add
5
8
Domain
x
Range
y
NOW LET’S TRY TO PUT IT IN A TABLE!

8. DOMAIN RANGE
x y
1
2
3
4
5
FUNCTION TABLE
6
8
7
10
9
independent dependent on
the domain
Formula?
𝒚 = 𝒙 + 𝟓
𝒇(𝒙) = 𝒙 + 𝟓

9. Let’s have
some
more
examples!

10. RELATION
One to
one
One to
many
Many
to one
Function
Correspondence between two
variables, 𝑥 𝑎𝑛𝑑 𝑦, or as a set of
ordered pairs (𝑥, 𝑦) where 𝑥 is related
to 𝑦.
Relation

11.  The monthly wage of a laborer
depends upon the number of
hours he worked
REAL WORLD EXAMPLES
 The area of circle depends upon
its radius.

12. FUNCTIONS
A rule that says for
every input there is
one and only one
output.
 A relation in which
each element in the
domain corresponds
to exactly one
element in the range

13. I. Determine whether each relation represents a
function.
ASSESSMENT
1. 0
1
2
3
5
6
7
8
2. -2
-4
-6
-8
3
6
9
3. 1
2
3
4
-3
-4
-5
4. 1
2
3
4
5
10
15

14. II. Determine whether the correspondence
depicted in each table is a function or not.
ASSESSMENT
Subject Call No.
Trigonometry 510
Algebra 512
Chemistry 513
Geometry 516
Appliance Price in
pesos
Microwave
Oven
12, 000
Refrigerator 14, 000
Washing
Machine
TV Set 18, 000
1. 2.

15. I. Determine whether the correspondence
depicted in each table is a function or not.
ASSESSMENT
Time of Day Temperatur
e in
Celsius
6 AM 27° C
8 AM 30° C
12 PM 33° C
2 PM 31° C
Student Sports
Chris Badminton
Alvin Soccer
Marichu Volleyball
Joie Basketball
4.3.

16. 1. 𝑓 𝑥 = 2𝑥 + 5 ; choose three values of x
2. f(x) = 3𝑥 − 2 ; choose three values of x
III. Give the output of the following functions and write it
in a function table.
ASSESSMENT
IV. List down two real- world example or scenario of the
following:
1. Relation which is a function
2. Relation which is not a function