FUNCTIONS
General Mathematics
Learning Objectives:
At the end of the session, students
should be able to:
1.define functions and relations;
2.relate the concepts of functions in real
life situations; and
3.participate in the class actively.
Review : Operations
• 5 + 9 =
• 2 + -8 =
• -14 + -7 =
• -2 + 18 =
14
-6
-21
16
Review : Operations
• 5 - 4 =
• 6 - 13 =
• -4 - 7 =
• 7 – (-5) =
1
-7
-11
12
Review : Operations
• (5) (7) =
• (9) (-6) =
• (-7) (12) =
• (-5) (-3) =
35
-54
-84
15
Review : Operations
• 20 / 5 =
• 15 / -5 =
• -16 / -2 =
• -30 / 6 =
4
-3
8
-5
RELATION
Refers to the correspondence of two sets.
x y
corresponds
depends
INPUT - OUTPUT
INPUT
x y
corresponds
depends
OUTPUT
RELATION
3
2
8
7
5
9
4
1
DOMAIN RANGE
RELATION
2
7
5
9
4
1
RELATION
3
2
8
7
9
4
function
Relation in which each element of the Domain is paired
with exactly ONE element of the Range.
x y
corresponds
ONE AND ONLY
ILLUSTRATION OF FUNCTIONS
a.Set of Ordered Pair
b.Mapping or Arrow Diagram
c.Graphing
A. SET OF ORDERED PAIR
1. {(3,2), (4,0), (5,1), (2,3)}
2. {(1,2), (0,3), (1,6), (5,4)}
3. {(3,4), (3,0), (3,1), (3,3)}
4. {(4,2), (3,2), (6,2), (5,2)}
5. {(5,3), (5,2), (3,2), (3,4)}
B. DIAGRAM
3
2
8
7
5
9
4
1
FUNCTION?
2
5
9
4
1
FUNCTION?
3
2
8
7
9
4
C. GRAPHING
VERTICAL LINE TEST
(Pencil Test)
If any vertical line passes through more
than one point of the graph, then that
relation is not a function.
C. GRAPHING
ACTIVITY
1.{(-3,1), (0,2), (2,4)}
2.{(1,5), (1,3), (4,5)}
3.{(5,6), (-3,0), (1,1), (-3,6)}
4.{(-2,1), (-1,-1), (0,1), (-1,1)}
5.y = 3x

Lesson 1 INTRODUCTION TO FUNCTIONS

Editor's Notes

  • #8 Imagine yourself that you were working in a gasoline station and you need to load two different engines. One is a truck and one is a car. Which engine would you load its tank firsts in order for them to finish almost at the same time.