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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?

Objective

SWBAT define and identify functions

SWBAT will identify and plot points in a
coordinate plane
FUNCTIONrepresents a relationship between one
variable to another.
The horizontal axis
(x-axis) is labeled
with the input
variable.
Consists of the following:
DOMAIN containing numbers called
RANGE containing numbers called
Each input must be paired with only
ONE output
INPUTS
OUTPUTS
The vertical axis
(y-axis) is
labeled with the
output variable.
“To Be or Not To Be” a FUNCTION
Input
Output
3
1
6
2
9
2
12
1
FUNCTION
3
6
9
12
1
2
2
1
The pairing is a function because
each input is paired with exactly
one output.
Input 2
Output 0
2
1
4
2
7
3
NOT A FUNCTION
2
4
7
0
1
2
3
The pairing is not a function
because each input is
not paired with exactly one output.
“To Be or Not To Be” a FUNCTION
Input
Output
3
5
5
7
3
1
5
3
NOT A FUNCTION
3
5
5
1
2
3
The pairing is not a function
because each input is
not paired with exactly one output.
Input 2
Output 0
4
1
6
0
8
1
FUNCTION
2
4
6
8
0
1
0
1
The pairing is a function because
each input is paired with exactly
one output.
Chapter 4 “Graphing Linear
Equations and Functions”
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(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
Coordinate Plane
y-axis
Quadrant II
(-,+)
Origin
(0,0)
Quadrant I
(+,+)
x-axis
Quadrant III
(-,-)
Quadrant IV
(+,-)
ordered
pair
Plotting Points (2,4)
(input, output)
y-axis
(-3,4)
5
C
4
A
3
(2,-3)
2
x – coordinate
(input)
1
-6
-5
-4
-3 -2 -1
0
1
2
3
-1
5
6
y – coordinate
(output)
-2
(-6,-4)
4
-3
D
-4
-5
B
x-axis
Graphing a Function
y = 4 – 2x with
Graph the function
the domain -2, -1, 0, 1, and 2. Then
identify the range of the function.
y  4  2x
x
y
-2
8
-1
0
6
4
1
2
2
0
The range of the function
is 8, 6, 4, 2, 0.
y-axis
10
(-2,8)
8
(-1,6)
6
4
(0,4)
(1,2)
2
-12 -10 -8
x-axis
-6 -4 -2
0
2
-2
-4
-6
-8
-10
4
(2,0)
6
8
10 12
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 1
Make a table by substituting
the domain values into the
function.
STEP 2
List the ordered pairs:
(– 2, – 5),(– 1, – 3), (0, –
1), (1, 1), (2, 3).Then
graph the function.
STEP 3
Identify the
range. The
range consists
of the y-values
from the table:
– 5, – 3, – 1, 1,
and 3.
Graph a Table
In 1920 the ratification of the 19th amendment to
the United States Constitution gave women the
right to vote. The table shows the number (to the
nearest million) of votes cast in presidential
elections both before and since women were able
to vote.
Years before or
since 1920
– 12
–8
–4
0
4
8
12
Votes (millions)
15
15
19
27
29
37
40
a.
Explain how you know that the table represents a function.
b.
Graph the function represented by the table.
Graph a function
SOLUTION
a. The table represents a function because
each input has exactly one output.
b. To graph the function, let x be the
number of years before or since 1920.
Let y be the number of votes cast (in
millions).
NJASK7 Prep
Homework
Text p. 209, #4-32 even & 36, 38