Do Now 10/22/09

1
Do Now 10/22/09

• Copy HW in your planner.
• Text p. 209, 4-32 even 36, 38
• Take out HW from last night.
• Cumulative Test Chapters 1-3.
• Open your textbook to page 35 and define the
  word FUNCTION in your notebook. Can you think of
  something that is a function in real life?

2
Objective

• SWBAT define and identify functions
• SWBAT will identify and plot points in a
  coordinate plane

3

• FUNCTION-

The horizontal axis (x-axis) is labeled with the
input variable.
represents a relationship between one variable to
another.
Consists of the following
DOMAIN containing numbers called
INPUTS
RANGE containing numbers called
OUTPUTS
The vertical axis (y-axis) is labeled with the
output variable.
Each input must be paired with only ONE output
4
To Be or Not To Be a FUNCTION
FUNCTION
NOT A FUNCTION
The pairing is a function because each input is
paired with exactly one output.
The pairing is not a function because each input
is not paired with exactly one output.
5
To Be or Not To Be a FUNCTION
FUNCTION
NOT A FUNCTION
The pairing is not a function because each input
is not paired with exactly one output.
The pairing is a function because each input is
paired with exactly one output.
6
Chapter 4 Graphing Linear
Equations and Functions

• (4.1) Plot Points in a Coordinate Plane
• (4.2) Graph Linear Equations
• (4.3) Graph Using Intercepts
• (4.4) Find Slope and Rate of Change
• (4.5) Graph Using Slope-Intercept Form
• (4.7) Graph Linear Functions

7
Coordinate Plane
y-axis
Quadrant I (,)
Quadrant II (-,)
Origin (0,0)
x-axis
Quadrant III (-,-)
Quadrant IV (,-)
8
Plotting Points
ordered pair
(2,4) (input, output)
y-axis
(-3,4)
5
C
4
A
3
(2,-3)
2
x coordinate (input)
1
0
1
2
3
4
5
6
-6
-5
-4
-3
-2
-1
-1
y coordinate (output)
-2
(-6,-4)
-3
B
-4
D
-5
x-axis
9
Graphing a Function
Graph the function y 4 2x with the domain
-2, -1, 0, 1, and 2. Then identify the range of
the function.
y-axis
10
(-2,8)
8
x y





(-1,6)
6
-2
8
4
(0,4)
(1,2)
2
-1
6
0
4
0
2
4
6
8
10
12
-12
-10
-8
-6
-4
-2
x-axis
(2,0)
1
2
-2
2
0
-4
-6
The range of the function is 8, 6, 4, 2, 0.
-8
-10
10
Graph a Function
Graph the function y 2x 1 with domain 2,
1, 0, 1, and 2. Then identify the range of the
function.
SOLUTION
STEP 2
STEP 3
STEP 1
List the ordered pairs ( 2, 5),( 1, 3),
(0, 1), (1, 1), (2, 3).Then graph the function.
Identify the range. The range consists of the
y-values from the table 5, 3, 1, 1, and 3.
Make a table by substituting the domain values
into the function.
11
Graph a Table
Years before or since 1920 12 8 4 0 4 8 12
Votes (millions) 15 15 19 27 29 37 40
12

Graph a function
SOLUTION
13
Homework
NJASK7 Prep

• Text p. 209, 4-32 even 36, 38