Graphing Functions

2. You should be able to:
1. Determine an
algebraic expression for
a situation.
2. Create a function
table
3. Plot points on a
coordinate plane

3. Step 1: To graph a
function, use a function
table to determine your
coordinate points.
(1, 2)
Input Output
(2,
1
2
4) (3,
2
4
6) (4,
3
6
4
8
8)

4. Step 2: Plot the points
on a coordinate plane.
(1, 2)
(2,
4) (3,
6) (4,
8)
10
9
8
7
6
5
4
3
2
1
0 1 2 3 4 5 6 7 8 9 10

5. Step 3: Connect the dots
if appropriate. Begin at
the origin.
10
9
(1, 2)
8
7
(2,
6
5
4) (3,
4
3
6) (4,
2
1
8)
0 1 2 3 4 5 6 7 8 9 10

6. Step 4: Write the
function using the
standard notation y = kx
k is known as
the constant of
proportionality
10
9
8
7
6
5
4
3
2
1
0 1 2 3 4 5 6 7 8 9 10
HUH?

7. Constant of ProportionalityThe constant value of the
ratio of two proportional
quantities.
In other words, the output
increases or decreases by
the same multiple each
time.
Y = 2X
2 is the constant

8. Step 5: Describe the
characteristics of the
graph
10
9
8
7
6
5
4
3
2
1
0 1 2 3 4 5 6 7 8 9 10
Is it
increasing?
Decreasing?
Staying
the same?

9. Step 6: Extend the graph
to find other values of the
function.
10
9
8
7
6
5
4
3
2
1
0 1 2 3 4 5 6 7 8 9 10
What would
be the value
if x=11?

10. The
End