# Wk4 Functions and Graphing Techniques Complete the attached document below about functions and graphing techniques Chapter 2 Functions and Their Graphs Cha

Wk4 Functions and Graphing Techniques Complete the attached document below about functions and graphing techniques Chapter 2 Functions and Their Graphs
Chapter 2: Functions and Their Graphs
Section 2.4: Library of Functions; Piecewise-defined Functions
In the real world, seldom can data be represented by just one function. More often, data changes
over time and must be represented by many different functions. When a function is defined by
different equations on different parts of its domain, it is called a piecewise-defined function.
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Author in Action: Graph Functions Listed in the Library of Functions (6:07)Video
Be able to fill in the information for all of these functions.
Before we begin looking at piecewise-defined functions, we must make sure we are familiar with
a lot of different functions, which we will call our “library of functions.” It’s important that you
know the properties of each of the key functions here. Being able to visualize basic functions
will be helpful in later topics such as nonlinear systems and graphing using transformations.
Exploration 1: Graph the Functions Listed in the Library of Functions
For each of the functions in our library, fill in the table of values, graph the function, then
complete the table of properties.
Identity Function: y = x
x
−2
−1
y
0
1
2
Properties
Domain:
Range:
x-intercept(s):
y-intercept:
Symmetry:
Interval the function is decreasing:
Interval the function is increasing:
Local maxima/Minima:
Absolute maxima/Minima:
Sections 2.4 & 2.5
Square Function: y = x 2
x
−2
−1
y
0
1
2
Properties
Domain:
Range:
x-intercept(s):
y-intercept:
Symmetry:
Interval the function is decreasing:
Interval the function is increasing:
Local maxima/Minima:
Absolute maxima/Minima:
Cube Function: y = x 3
x
−2
−1
y
0
1
2
Properties
Domain:
Range:
x-intercept(s):
y-intercept:
Symmetry:
Interval the function is decreasing:
Interval the function is increasing:
Local maxima/Minima:
Absolute maxima/Minima:
Chapter 2 Functions and Their Graphs
Square Root Function: y = x
x
−4
−1
y
0
1
4
Properties
Domain:
Range:
x-intercept(s):
y-intercept:
Symmetry:
Interval the function is decreasing:
Interval the function is increasing:
Local maxima/Minima:
Absolute maxima/Minima:
Cube Root Function: y = 3 x
x
−8
y
−1
0
1
8
Properties
Domain:
Range:
x-intercept(s):
y-intercept:
Symmetry:
Interval the function is decreasing:
Interval the function is increasing:
Local maxima/Minima:
Absolute maxima/Minima:
Sections 2.4 & 2.5
Reciprocal Function: y =
1
x
x
−2
−1
y
0
1
2
Properties
Domain:
Range:
x-intercept(s):
y-intercept:
Symmetry:
Interval the function is decreasing:
Interval the function is increasing:
Local maxima/Minima:
Absolute maxima/Minima:
Absolute Value Function: y = x
x
−2
−1
y
0
1
2
Chapter 2 Functions and Their Graphs
Properties
Domain:
Range:
x-intercept(s):
y-intercept:
Symmetry:
Interval the function is decreasing:
Interval the function is increasing:
Local maxima/Minima:
Absolute maxima/Minima:
Some other important functions to know:
The Constant Function: f ( x) = b where b is a real number.
These graphs will always be a ___________________ line
with a y – intercept of ________.
Sections 2.4 & 2.5
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Author in Action: Graph Piecewise-defined Functions (10:00)Video
Now that we have our “library of functions,” let’s look at piecewise – defined functions.
Post 1
Definition: When a function is defined by different __________ on different parts of its
________, it is called a piecewise-defined function.
Example 1*: Graph Piecewise – Defined Functions
The function f is defined as
 x2
if x  0

f ( x ) = 2
if x = 0
 x + 2 if x  0

(a) Find f ( −2) , f ( 0) , and f ( 3)
(b) Determine the domain of f.
(c) Graph f.
(d) Use the graph to find the range of f.
(e) Is f continuous on its domain?
Chapter 2 Functions and Their Graphs
Section 2.5: Graphing Techniques: Transformations
In the last section we looked at our “library of functions” and made sure we could recognize any
of them. In most applications however, we are often asked to graph or recognize a function that
is “almost” like one that we already know. In this section, we will look at some of these
functions and develop techniques for graphing them. Collectively, these techniques are referred
to as transformations.
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Author in Action: Graph Functions Using Vertical and Horizontal Shifts (9:51)Video
Post 2
Exploration 1: Graph Functions Using Vertical Shifts
(a) Sketch the graph of y = x 2
(b) On the same set of axes sketch the graphs
y = x2 + 2 .
of
(c) What is the connection between the
graphs?
(d) Test your connection by predicting the graph of y = x 2 − 3 and then graphing it.
If we were asked to write the transformations y = x 2 + 2 and y = x 2 − 3 in terms of the original
function, we could say that y = x 2 + 2 = f ( x) + 2 and y = x 2 − 3 = f ( x) − 3 .
Sections 2.4 & 2.5
Summary of Vertical Shifts
• If a positive real number k is added to the output of a function, y = f ( x) , the graph of
the new function, y = f ( x) + k , is the graph of f shifted _______________ k units.

If a positive real number k is subtracted from the output of a function, y = f ( x) , the
graph of the new function, y = f ( x) − k is the graph of f shifted __________ k units.
Post 3
Exploration 2*: Graph Functions Using Horizontal Shifts
(e) Sketch the graph of y = x 2
(f) On the same set of axes sketch the graphs
= ( − 2)2 .
of
(g) What is the connection between the
graphs?
(h) Test your connection by predicting the graph of = ( + 2)2 and then graphing it.
If we were asked to write the transformations = ( − 3)2 and = ( + 3)2 in terms of the
original function, we could say that = ( − 2)2 = ( − 2) and
= ( + 3)2 = ( + 3).
Summary of Horizontal Shifts
Chapter 2 Functions and Their Graphs

If the argument x of a function f is replaced by x − h, h  0 , the graph of the new function
y = f ( x − h) is the graph of f___________________________ h units.

If the argument x of a function f is replaced by x + h, h  0 , the graph of the new function
y = f ( x + h) is the graph of f___________________________ h units.
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Author in Action: Functions Compressions and Stretches Part I (10:22)Video
Post 4
Exploration 3*: Graph Functions Using Vertical Stretches and Compressions
1
On the same set of axes, sketch the graphs of ( ) = | |, = 2 ( ), and y = f ( x )
2
Summary of Vertical Stretches and Compressions
The graph of y = af ( x) when a  0 is a transformation of the graph y = f ( x) .
Sections 2.4 & 2.5

If a  1 , then the graph of the original function is ______________ vertically by a factor
of a units.

If 0  a  1, then the graph of the original function is ______________ vertically by a
factor of a units.
Post 5
Exploration 4: Graph Functions Using Horizontal Stretches and Compressions
On the same set of axes, sketch the graphs of ( ) = √ , = (2 ).
Chapter 2 Functions and Their Graphs
Summary of Horizontal Stretches and Compressions:
The graph of y = f (ax) when a  0 is a transformation of the graph y = f ( x) .
• If a  1 , then the graph of the original function is ____________ horizontally by a factor
1
of
units.
a

If 0  a  1, then the graph of the original function is ____________ horizontally by a
1
factor of
units.
a
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Author in Action: Functions Compressions and Stretches Part II (6:00)Video
This shows how to combine a horizontal compression and a vertical stretch.
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Author in Action: Graph Functions Using Reflections about the x-Axis and the y-Axis
(4:40)Video
This shows how to combine horizontal and vertical reflections.
Summary of Horizontal and Vertical Reflections:
The graph of y = − f ( x ) is a transformation of the graph y = f ( x) . It reflects the graph of the
original function over the __________ axis.
The graph of y = f ( − x ) is a transformation of the graph y = f ( x) . It reflects the graph of
the original function over the __________ axis.
Sections 2.4 & 2.5
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Author in Action: Summary of Transformations (13:56)
Know the table:
Summary of Transformations*
To Graph:
Draw the Graph of f and :
Vertical Shifts
Functional Change to f ( x ) :
y = f ( x) + k , k  0
y = f ( x) − k, k  0
Horizontal Shifts
y = f ( x + h) , h  0
y = f ( x − h) , h  0
Compressing or Stretching
y = af ( x ) , a  0
y = f ( ax ) , a  0
Reflection about the x – axis
y = − f ( x)
Reflection about the y – axis
y = f ( −x)