Algebra I Module 3, Topic C, Lesson 17: Student Version

Lesson 17
NYS COMMON CORE MATHEMATICS CURRICULUM
M3
ALGEBRA I
Lesson 17: Four Interesting Transformations of Functions
Classwork
Exploratory Challenge 1
Let 𝑓(π‘₯) = |π‘₯|, 𝑔(π‘₯) = 𝑓(π‘₯) βˆ’ 3, and β„Ž(π‘₯) = 𝑓(π‘₯) + 2 for any real number π‘₯.
a.
Write an explicit formula for 𝑔(π‘₯) in terms of |π‘₯| (i.e., without using 𝑓(π‘₯) notation).
b.
Write an explicit formula for β„Ž(π‘₯) in terms of |π‘₯| (i.e., without using 𝑓(π‘₯) notation).
c.
Complete the table of values for these functions.
𝒙
𝒇(𝒙) = |𝒙|
π’ˆ(𝒙) = 𝒇(𝒙) βˆ’ πŸ‘
𝒉(𝒙) = 𝒇(𝒙) + 𝟐
βˆ’3
βˆ’2
βˆ’1
0
1
2
3
Lesson 17:
Four Interesting Transformations of Functions
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NYS COMMON CORE MATHEMATICS CURRICULUM
Lesson 17
M3
ALGEBRA I
d.
Graph all three equations: 𝑦 = 𝑓(π‘₯), 𝑦 = 𝑓(π‘₯) βˆ’ 3, and 𝑦 = 𝑓(π‘₯) + 2.
e.
What is the relationship between the graph of 𝑦 = 𝑓(π‘₯) and the graph of 𝑦 = 𝑓(π‘₯) + π‘˜?
f.
How do the values of 𝑔 and β„Ž relate to the values of 𝑓?
Lesson 17:
Four Interesting Transformations of Functions
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Lesson 17
NYS COMMON CORE MATHEMATICS CURRICULUM
M3
ALGEBRA I
Exploratory Challenge 2
1
2
Let 𝑓(π‘₯) = |π‘₯|, 𝑔(π‘₯) = 2𝑓(π‘₯), and β„Ž(π‘₯) = 𝑓(π‘₯) for any real number π‘₯.
a.
Write a formula for 𝑔(π‘₯) in terms of |π‘₯| (i.e., without using 𝑓(π‘₯) notation).
b.
Write a formula for β„Ž(π‘₯) in terms of |π‘₯| (i.e., without using 𝑓(π‘₯) notation).
c.
Complete the table of values for these functions.
𝒙
𝒇(𝒙) = |𝒙|
π’ˆ(𝒙) = πŸπ’‡(𝒙)
𝒉(𝒙) =
𝟏
𝒇(𝒙)
𝟐
βˆ’3
βˆ’2
βˆ’1
0
1
2
3
Lesson 17:
Four Interesting Transformations of Functions
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This file derived from ALG I-M3-TE-1.3.0-08.2015
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Lesson 17
NYS COMMON CORE MATHEMATICS CURRICULUM
M3
ALGEBRA I
d.
1
2
Graph all three equations: 𝑦 = 𝑓(π‘₯), 𝑦 = 2𝑓(π‘₯), and 𝑦 = 𝑓(π‘₯).
1
2
Given 𝑓(π‘₯) = |π‘₯|, let 𝑝(π‘₯) = βˆ’|π‘₯|, π‘ž(π‘₯) = βˆ’2𝑓(π‘₯), and π‘Ÿ(π‘₯) = βˆ’ 𝑓(π‘₯) for any real number π‘₯.
e.
Write the formula for π‘ž(π‘₯) in terms of |π‘₯| (i.e., without using 𝑓(π‘₯) notation).
f.
Write the formula for π‘Ÿ(π‘₯) in terms of |π‘₯| (i.e., without using 𝑓(π‘₯) notation).
Lesson 17:
Four Interesting Transformations of Functions
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Lesson 17
NYS COMMON CORE MATHEMATICS CURRICULUM
M3
ALGEBRA I
g.
1
2
Complete the table of values for the functions 𝑝(π‘₯) = βˆ’|π‘₯|, π‘ž(π‘₯) = βˆ’2𝑓(π‘₯), and π‘Ÿ(π‘₯) = βˆ’ 𝑓(π‘₯).
𝒙
𝒑(𝒙) = βˆ’|𝒙|
𝒒(𝒙) = βˆ’πŸπ’‡(𝒙)
𝟏
𝟐
𝒓(𝒙) = βˆ’ 𝒇(𝒙)
βˆ’3
βˆ’2
βˆ’1
0
1
2
3
h.
Graph all three functions on the same graph that was created in part (d). Label the graphs as 𝑦 = 𝑝(π‘₯),
𝑦 = π‘ž(π‘₯), and 𝑦 = π‘Ÿ(π‘₯).
i.
How is the graph of 𝑦 = 𝑓(π‘₯) related to the graph of 𝑦 = π‘˜π‘“(π‘₯) when π‘˜ > 1?
j.
How is the graph of 𝑦 = 𝑓(π‘₯) related to the graph of 𝑦 = π‘˜π‘“(π‘₯) when 0 < π‘˜ < 1?
k.
How do the values of functions 𝑝, π‘ž, and π‘Ÿ relate to the values of functions 𝑓, 𝑔, and β„Ž, respectively?
What transformation of the graphs of 𝑓, 𝑔, and β„Ž represents this relationship?
Lesson 17:
Four Interesting Transformations of Functions
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NYS COMMON CORE MATHEMATICS CURRICULUM
Lesson 17
M3
ALGEBRA I
Exercise
Make up your own function 𝑓 by drawing the graph of it on the Cartesian plane below. Label it as the graph of the
1
4
equation 𝑦 = 𝑓(π‘₯). If 𝑏(π‘₯) = 𝑓(π‘₯) βˆ’ 4 and 𝑐(π‘₯) = 𝑓(π‘₯) for every real number π‘₯, graph the equations 𝑦 = 𝑏(π‘₯) and
𝑦 = 𝑐(π‘₯) on the same Cartesian plane.
Lesson 17:
Four Interesting Transformations of Functions
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NYS COMMON CORE MATHEMATICS CURRICULUM
Lesson 17
M3
ALGEBRA I
Problem Set
Let 𝑓(π‘₯) = |π‘₯| for every real number π‘₯. The graph of 𝑦 = 𝑓(π‘₯) is shown below. Describe how the graph for each
function below is a transformation of the graph of 𝑦 = 𝑓(π‘₯). Then, use this same set of axes to graph each function for
Problems 1–5. Be sure to label each function on your graph (by 𝑦 = π‘Ž(π‘₯), 𝑦 = 𝑏(π‘₯), etc.).
3
2
1.
π‘Ž(π‘₯) = |π‘₯| +
2.
𝑏(π‘₯) = βˆ’|π‘₯|
3.
𝑐(π‘₯) = 2|π‘₯|
4.
𝑑(π‘₯) = |π‘₯|
5.
𝑒(π‘₯) = |π‘₯| βˆ’ 3
1
3
Lesson 17:
Four Interesting Transformations of Functions
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This file derived from ALG I-M3-TE-1.3.0-08.2015
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Lesson 17
NYS COMMON CORE MATHEMATICS CURRICULUM
M3
ALGEBRA I
6.
Let π‘Ÿ(π‘₯) = |π‘₯| and 𝑑(π‘₯) = βˆ’2|π‘₯| + 1 for every real number π‘₯. The graph of 𝑦 = π‘Ÿ(π‘₯) is shown below.
Complete the table below to generate output values for the function 𝑑, and then graph the equation 𝑦 = 𝑑(π‘₯) on
the same set of axes as the graph of 𝑦 = π‘Ÿ(π‘₯).
𝒙
𝒓(𝒙) = |𝒙|
𝒕(𝒙) = βˆ’πŸ|𝒙| + 𝟏
βˆ’2
βˆ’1
0
1
2
Lesson 17:
Four Interesting Transformations of Functions
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Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
NYS COMMON CORE MATHEMATICS CURRICULUM
Lesson 17
M3
ALGEBRA I
7.
Let 𝑓(π‘₯) = |π‘₯| for every real number π‘₯. Let π‘š and 𝑛 be functions found by transforming the graph of 𝑦 = 𝑓(π‘₯).
Use the graphs of 𝑦 = 𝑓(π‘₯), 𝑦 = π‘š(π‘₯), and 𝑦 = 𝑛(π‘₯) below to write the functions π‘š and 𝑛 in terms of the function
𝑓. (Hint: What is the π‘˜?)
π’š = 𝒏(𝒙)
π’š = π’Ž(𝒙)
Lesson 17:
Four Interesting Transformations of Functions
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This file derived from ALG I-M3-TE-1.3.0-08.2015
π’š = 𝒇(𝒙)
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