Download Function Rules for Graphs

Function Rules for Graphs
Learning Goal for Focus 3 (HS.A-CED.A.1, HS.F-IF.A.1 & 2, HS.F-IF.B.4 & 5):
The student will understand the concept of a function and use
of function notation.
4
3
2
1
0
In addition to level
3.0 and above and
beyond what was
taught in
class, the student
may:
· Make connection
with other
concepts in math
· Make connection
with other content
areas.
The student will understand the
concept of a function and use of
function notation.
- Evaluate functions for given
inputs.
- Interpret key features of
graphs and tables of a function.
- Sketch graphs of functions.
- Determine the domain of the
equation or graph of a function
and what it may represent in
context.
- Convert a table, graph, set of
ordered pairs, or description
into function notation by
identifying a rule.
- Identify numbers that are not
in the domain of a function.
[f(x) = 1/x x≠ 0 or f(x) = 𝑥 x ≠
a negative]
The student will be
able to understand
the concept of a
function.
- Correctly use
function terminology
(domain, range,
f(x)).
- Determine if a
relationship given in
a table, graph, or
words depicts a
function.
With help from
the
teacher, the
student has
partial success
with function
terminology,
function
notation and
determining if
a relation table
or graph depict
a function.
Even with help,
the student has
no success
understanding
the concept of
a function.
Make graphs from a function…

Graph the function f(x) = 2x – 3.

Start by making a table of values.

Graph the ordered pairs.

Connect the dots.
x
f(x)
-2
-7
-5
-3
-1
1
-1
0
1
2
Write a function from a graph.

Step 1: Find where the line will cross the yaxis.




(0, 2)
Step 2: Is the line going up or down?

Up = positive slope

Down = negative slope
Step 3: Calculate the slope.

Find two points on the line.

Count the number of spaces up or down
(numerator).

Count the number of spaces to the right
(denominator).

Reduce the fraction = this is the slope of the line.
2
1
Step 4: Write the function:
2=2
1

f(x) = (slope)(x) + (where it crosses the y-axis)

f(x) = 2x + 2
Write a function from a graph.

Step 1: Find where the line will cross the yaxis.




(0, 0)
Step 2: Is the line going up or down?

Up = positive slope

Down = negative slope
Step 3: Calculate the slope.

Find two points on the line.

Count the number of spaces up or down
(numerator).

Count the number of spaces to the right
(denominator).

Reduce the fraction = this is the slope of the line.
1
3
Step 4: Write the function:
-1
3

f(x) = (slope)(x) + (where it crosses the y-axis)

f(x) = -1/3x
Write a function from a graph.

Step 1: Find where the line will cross the yaxis.




(0, -2)
Step 2: Is the line going up or down?

Up = positive slope

Down = negative slope
Step 3: Calculate the slope.

Find two points on the line.

Count the number of spaces up or down
(numerator).

Count the number of spaces to the right
(denominator).

Reduce the fraction = this is the slope of the line.
3
2
Step 4: Write the function:
-3
2

f(x) = (slope)(x) + (where it crosses the y-axis)

f(x) = -3/2x - 2