1. Alegebra 2A
Function
Lesson 1
Objective: Relations, and Functions

2. 1. Relation
A set of ordered pairs (x, y).
Examples: (7, 2), (0, -5), (-2.4, -18),…
2. Domain – The first coordinate (x) of a
relation. (Independent Variable)
3. Range – The second coordinate (y) of
a relation. (Dependent Variable)

3. Examples: 4. Function – A relation in which each
element in the domain (x) corresponds to one, and only one, element in the range (y).
Examples:
State the domain and range of each
relation. Also determine if it is a
function.
Ex1

4. (a) (8, 5), (7, -2), (-2, 9), (0, 3)
(b) (-3, 4), (14, 0), (6, 4), (2, 8)
(c) (1, 6), (1, -7), (0, 0), (5, 13) d)

5. One-To-One Correspondence
A situation in which each domain
value (x) corresponds to exactly
one element in the range (y), and
vice versa.
Example: (7, 9), (-1, 15), (2, 0), (8, -3)

6. Based on each graph below, which represents a function?
Ex2 b.
c d.

7. Vertical Line Test
If any vertical line intersects a graph
in more than one point, then the
graph is not a function.

8. Ex. 3 For the graph of f(x) below:
Find the output for the input value 4.
Find the inputs whose output value is 0.
Find f(1)
If f(x) = -2, then x = ?
Find f(-2)
State the domain and range of f(x).
Is f(x) a function? A 1–1 function?
Ex. 3

9. For g(x) = x2 + 7x – 2, find: a) b) c) d) e) f)
Ex. 4

10. Ex. 5

11. Ex. 6
Graph the functions f(x) = 2x and
g(x) = 2x + 4 on the same axis.
What do you notice? Why is this
so?

12. Ex. 7
Use the graph of each function to
Identify its domain and range. a)

13. b)

14. c)

15. d)

16. Function Lesson
1 Assignment
Numbers (1 – 14)