UNIT 1:
Key Features &
Transformations of
Functions
Algebra 2
Dr. Dam – [email protected]
Period:
Name:
ID:
SUCCESS CRITERIA
I can… identify the function family of a graph/equation and label all the key features.
I can explain… how transformations affect a function and its key features.
I can justify… why the different representations of a function are equivalent.
I can apply… transformations to model a scenario.
MATH FUNCTION DANCE :)
TABLE OF CONTENTS
LESSON TITLE OPTIONAL PG #
1.1 Definition of Functions & Function Notation 4-5
1.2 Function Families & their Parent Functions 6-10
1.3 Key Features of Functions 11-14
1.4 Domain & Range 15-16
1.5 Transformations of Functions 17-19
1.6 Piecewise Functions 20-21
2
Lesson 1.1 - Definition of Functions & Function Notation
Function
Function Notation
Example 1: Let f (x) = x2 + 3 . Evaluate f (x) at x = − 1, 0, and 2 . Make a table using these values.
Example 2: Let g(x) = √ x − 1 . What values can be inputted into g(x) ? Explain your reasoning.
You Try: Evaluate the three functions below.
f (x) = x3 at x = − 2 and 1/2 g(x) = |x| + 2 at x = − 4 and 7 h(x) = 1 at x = − 4 and 0
x
3
Classwork
1) Let f (x) = 2x − 3 ; Find f (6) .
2) Let g(x) = x2 − 4x ; Find g(− 1) .
3) Let h(x) = |3x| − 2 ; Find h(− 2) .
4) Let v(t) = 4t + 3 ; Find v(2) .
5) Let f (x) = (x − 2)2 ; Create a table of values for x = − 1, 0, 1, 2, 3 .
Then, graph the values and draw the function.
6) In the graph below, f (4) = 1. Use the graph to determine: f (2), f (8), and f (0) .
7) Using the graph above, what values of x make f (x) = 1 ? Explain your reasoning.
4
Lesson 1.2 - Function Families & their Parent Functions
LINEAR FAMILY Parent: f (x) = x Parent Graph
QUADRATIC FAMILY Parent Graph
CUBIC FAMILY x f(x ) Parent Graph
-2
-1
0
1
2
Parent: f (x) = x2
x f( x )
-2
-1
0
1
2
Parent: f (x) = x3
x f( x)
-2
-1
0
1
2
5
SQUARE ROOT FAMILY Parent: f (x) = √x Parent Graph
CUBE ROOT FAMILY Parent Graph
ABSOLUTE VALUE FAMILY x f( x ) Parent Graph
-1
0
1
2
4
Parent: f (x) = √3 x
x f( x)
-8
-1
0
1
8
Parent: f (x) = |x|
x f( x)
-2
-1
0
1
2
6
EXPONENTIAL FAMILY Parent: f (x) = 2x Parent Graph
RATIONALFAMILY Parent Graph
RATIONAL FAMILY Parent Graph
x f( x)
3
2
1
0
-1
-2
Parent: f (x) = 1
x
x f( x )
10
1
1/10
0
-1/10
-1
-10
Parent: f (x) = 1
x2
x f(x)
10
1
1/10
0
-1/10
-1
-10
7
LOGARITHMIC FAMILY Parent: f (x) = log x Parent Graph
SINE FAMILY Parent Graph
COSINE FAMILY x f( x ) Parent Graph
-2
-1 8
0
1
2
4
10
Parent: f (x) = sin x
x f( x)
-π
- π/2
0
π/2
π
3π/2
2π
Parent: f (x) = cos x
x f(x)
-π
- π/2
0
π/2
π
3π/2
2π
Everyday Functions
9
Prerequisite Skill for Lesson 1.3 - Interval & Inequality Notation
Interval Inequality Number Line
10
Lesson 1.3 - Key Features of Functions
x-Intercept
y-Intercept
Relative Maximum
Relative Minimum
Increasing
Decreasing
End Behavior
How do we mathematically write these key features?
11
Example 1: The graph depicts the function. Identify the function’s intercepts; relative minimums and
maximums; absolute minimum and maximum; and intervals of increase/decrease.
You Try: For each graph identify the function’s intercepts; relative minimums and maximums;
absolute minimum and maximum; and intervals of increase/decrease.
If it does not exist, then write “DNE.”
12
Key Features Review
Domain:
Range:
x-intercept(s):
y- intercept(s):
Extrema:
Asymptote(s):
Increasing Behavior:
Decreasing Behavior:
End Behavior:
Domain:
Range:
x-intercept(s):
y- intercept(s):
Extrema:
Asymptote(s):
Increasing Behavior:
Decreasing Behavior:
End Behavior:
Domain:
Range:
x-intercept(s):
y- intercept(s):
Extrema:
Asymptote(s):
Increasing Behavior:
Decreasing Behavior:
End Behavior:
13
Lesson 1.4 - Domain & Range
Domain All possible inputs in a function (consider what can and cannot go into a function’s input). U se x-values.
Range All possible outputs in a function (consider what can and cannot go into a function’s output). Use y-values.
Example 1: Find the domain & range of f (x) = √x . Example 2: Find the domain & range of f (x) = x2
.
You Try: Determine the domain & range of each of the following parent functions below.
f (x) = |x| f (x) = x
Domain: Domain:
Range: Range:
f (x) = x3 f (x) = √3 x
Domain: Domain:
Range: Range:
14
f (x) = 2x f (x) = 1
x
Domain: Domain:
Range: Range:
Example 3: The graph shows f (x) = √x . Draw the graphs for g(x) = √x + 3 and h(x) = √x + 3 .
Determine the domain & range of g(x) and h(x) .
Consider how they changed from the parent function and why they changed.
Example 4: The graph shows f (x) = x2 . Draw the graphs for g(x) = x2 − 5 and h(x) = (x − 5)2 .
Determine the domain & range of g(x) and h(x) .
Consider how they changed from the parent function and why they changed.
15
Lesson 1.5 - Transformations of Functions
Translation
Dilation
Reflection
Translations Description Example
Example
f (x) + a Example
f (x) − a
f (x − a) 16
f (x + a)
Dilations Description
Description
k f (x)
1 f (x)
k
f (kx)
f( 1 x)
k
Reflections
− f (x)
f (− x)
*ORDER of transformations: 1) Dilations & Reflections 2) Translations
Example 1: Identify the parent function and transformations of each function. Then sketch each function.
f (x) = (x + 4)2 h(x) = = 2(x + 3)3
g(x) = − 3 |x| v(x) = 1 √− x + 4
2
Example 2: Given the graph of the parent function f (x) , describe the transformations for each function.
Then apply the transformation to the graph and label them respectively using a, b, c.
a) 2f (x − 5)
b) − f (x) − 3
c) 1 f (x + 3) − 2
2
Example 3: Write a possible function for each graph.
17
Transformations Review
Suppose (6, 1) is the point of the graph y = f (x) .
For each of the following, name the point on the graph, and then name the transformation.
1. y = f (3x)
2. y = f (x + 2)
3. y = f (x) + 5
4. y= 1 f (x)
2
5. y = f (− x)
6. y = f (x − 7)
7. y = 4f (x)
8. y = f( 1 x)
2
9. y = − f (x)
18
Lesson 1.6 - Piecewise Functions OPTIONAL
Piecewise Function A function defined by multiple functions on different intervals
Example 1: Determine the key features. Domain:
f (x) = Range:
Intercept(s):
Extrema:
Asymptote(s):
Increasing Behavior:
Decreasing Behavior:
End Behavior:
Example 2: Let f (x) be the parent function. Graph f (− x) + 2 .
Example 3: Let g(x) be the parent function shown in the graph. List the key features of g(x) .
Then perform the transformations described by the function 1 g(x − 3) − 2 .
2
19
Example 4: Let h(x) be the parent function shown in the graph. List the key features of h(x) .
Then perform the transformations described by the function − 2h(x) + 5 and h(2x) .
You Try: Let m(x) be the piecewise function shown.
a) Make a table showing at least 4 values of m(x) .
b) Identify the domain and range of m(x) .
c) Pick any transformation(s) to perform and show it in the blank graph.
Write the equation for your transformation(s).
20
21