honors alg 2 unit 2 packet

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1 HONORS ALGEBRA II UNIT 2: FUNCTIONS AND LINES TOPIC MATERIAL ASSIGNED A Day B Day CW HW Day 1 Wednesday, 9/2 Thursday, 9/3 Functions & Lines Guided Review FinishWorksheet Day 2 Friday, 9/4 Tuesday, 9/8 Linear Regression Guided Notes Day 2 HW Practice #1, #2 Day 3 Wednesday, 9/9 Formative #2 Thursday, 9/10 Formative #2 Linear Regression Graded Assignment ------------------------------ Day 4 Friday, 9/11 Monday, 9/14 Absolute Value Guided Notes Day 4 HW #1-12 Day 5 Tuesday, 9/15 Wednesday, 9/16 Absolute Value Guided Notes 1-5 HW #4-18, #28-30 Day 6 Thursday, 9/17 Formative #3 Friday, 9/18 Formative #3 Absolute Value Graphing Guided Notes Day 6 HW #1-12 Day 7 Monday, 9/21 Tuesday, 9/22 Review Lin Reg and Abs Val Study Day 8 Wednesday, 9/23 Thursday, 9/24 Test Lin Regression and Absolute Value ------------------------------- Day 9 Friday, 9/25 Tuesday, 9/29 Composition of Functions Notes Day 9 HW #1-23 Day 10 Wednesday, 9/30 Thursday, 10/1 Inverse Functions Notes Day 10-11 HW Evens Day 11 Friday, 10/2 Monday, 10/5 Graded Assignment Composition and Inverses Day 10-11 HW Odds Day 12 Tuesday, 10/6 Formative #4 Wednesday, 10/7 Formative #4 Modeling and Word Problems Day 12 Worksheet Day 13 Thursday, 10/8 Friday, 10/9 Review and Pre-Assessment Study Day 14 Monday, 10/12 Tuesday, 10/13 Cumulative Unit 2 Test --------------------------------- Broughton High School Honors Algebra 2 Unit 2 Name ___________________

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Page 1: Honors Alg 2 Unit 2 Packet

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HONORS ALGEBRA II – UNIT 2: FUNCTIONS AND LINES

TOPIC MATERIAL ASSIGNED

A Day B Day CW HW

Day 1 Wednesday, 9/2 Thursday, 9/3 Functions & Lines Guided

Review

FinishWorksheet

Day 2 Friday, 9/4 Tuesday, 9/8 Linear Regression Guided

Notes

Day 2 HW Practice #1, #2

Day 3 Wednesday, 9/9

Formative #2

Thursday, 9/10

Formative #2

Linear Regression

Graded Assignment

------------------------------

Day 4 Friday, 9/11 Monday, 9/14 Absolute Value Guided Notes Day 4 HW #1-12

Day 5 Tuesday, 9/15 Wednesday, 9/16 Absolute Value Guided Notes 1-5 HW #4-18, #28-30

Day 6 Thursday, 9/17

Formative #3

Friday, 9/18

Formative #3

Absolute Value Graphing

Guided Notes

Day 6 HW #1-12

Day 7 Monday, 9/21 Tuesday, 9/22 Review – Lin Reg and Abs Val Study

Day 8 Wednesday, 9/23 Thursday, 9/24 Test – Lin Regression and

Absolute Value

-------------------------------

Day 9 Friday, 9/25 Tuesday, 9/29 Composition of Functions

Notes

Day 9 HW #1-23

Day 10 Wednesday, 9/30 Thursday, 10/1 Inverse Functions Notes Day 10-11 HW Evens

Day 11 Friday, 10/2

Monday, 10/5

Graded Assignment –

Composition and Inverses

Day 10-11 HW Odds

Day 12 Tuesday, 10/6

Formative #4

Wednesday, 10/7

Formative #4

Modeling and Word Problems Day 12 Worksheet

Day 13 Thursday, 10/8 Friday, 10/9 Review and Pre-Assessment Study

Day 14 Monday, 10/12 Tuesday, 10/13 Cumulative Unit 2 Test ---------------------------------

Broughton High School

Honors Algebra 2

Unit 2

Name ___________________

Page 2: Honors Alg 2 Unit 2 Packet

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Functions and Lines Day 1 Guided Review

This worksheet covers some of the knowledge needed as a foundation in the next unit. All problems are Algebra 1 concepts. Use the internet, peers, or come in for tutoring if you have any gaps in knowledge. TRY EVERYTHING!

Terminology and Concepts: Slope – Intercept Form: bmxy

Standard Form: CByAx

Slope: 12

12

xx

yym

Set Builder Notation Example: Solve: x + 4 > 7 Answer: {x| x >3} Function: For each x, there exists only one y Common Terms: Domain/Independent/x Range/Dependent/y x-intercept/y-intercept I. The Basics

1. Consider the points: (3, -3), (1, -4), (0, 5), and (2, 5).

a. State the Domain: b. State the Range: c. Is this a function? _____ Why or why not?

2. Find the slope of the line passing through (3, -3) and (1, -4). 3. Write the equation of a line passing through (3, -3) and (1, -4) in slope-intercept form.

4. Write the equation of the above line in standard form. 5. Solve for x and write the answer in set builder notation:

a. 4(x – 3) + 7 = 9 b. bx – 4c = w

c. |x + 4| = 6

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II. Graphs

1. Graph: y = 3x – 6

2. Graph: y < ½x + 2 3. Graph: 3x – 2y 4

III. Analysis: The equation y – .23x = 0 relates the cost of operating a car (y) to the number of miles driven (x).

1. What does the number .23 tell you about the cost and miles driven? 2. What are the x- and y-intercepts and what do they tell you about the cost

and miles driven?

3. What would be an appropriate domain for this problem?

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Day 2 Linear Models Linear Regression

Example 1: Find an equation on your calculator passing through the points: (9, 2) (8, 0) y = _____________ Example 2: This is the number of bicycles produced in the US in millions from 1993 to 1996.

Year Bicycle Production

1993 9.9

1994 9.7

1995 8.8

1996 8.0

a. Create a scatter plot of the data. Use 1990 as year 0. b. Find a linear regression equation. y = _________________ c. Graph the regression equation on the scatter plot and compare. Does the linear regression equation fit your data? ___________________________________ d. Calculate the correlation coefficient. r = __________ What does this tell you about the data’s fit to the line? ___________________________________ e. Using your regression equation, predict (extrapolate) the number of bicycles that would be produced in 2000, 2007, and 2030: 2000: ________________________ 2007: ________________________ 2030: ________________________ Is the last answer valid? Why or why not? __________________________________

Calculator Buttons: Stat - Enter Type your x’s in L1 and your y’s in L2. 2nd Quit Stat - - Calc #4 Enter Twice. Calculator Buttons: Enter data as above. 2nd y= (Stat Plot) – Turn Plot On. Zoom #9 Calculator Buttons: Stat – Calc #4 (Don’t hit enter) Vars – y-vars - #1 #1 Enter Calculator Buttons: 2nd 0 (catalog) – Diagnostic ON – Enter Twice Recalculate regression equation

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Example 3: The chart shows the average ticket price for movies for given years in dollars. a. Find a linear regression equation: Use 1900 as year 0. y = ________________ b. Name the slope and y-intercept and interpret their meaning for this data: m= _______ b= ________ c. Calculate r = ___________. What does it tell you about the data? ___________________________________ ___________________________________ d. According to your equation, what would have been the cost of a movie in 1980? __________This is called interpolation. e. According to your equation, what will be the movie price in 2007? ____________ in 1880? ____________ What domain makes sense for this data? ________________________________ f. When does your equation predict movie prices will reach $10? ________________ g. Does a line seem to be the best model for this data?________________________ ___________________________________ h. Are there any outliers (look at scatter plot)? ______________________________

Year Average Ticket Price (dollars)

1935 0.25

1940 0.28

1948 0.38

1954 0.50

1958 0.69

1963 0.87

1967 1.43

1970 1.56

1974 1.89

1978 2.33

1982 2.93

1986 3.70

1990 4.21

1994 4.10

1998 4.68

2001 5.65

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Unit 2 Day 2 Assignment: #1 This data was collected by a college psychology class to determine the effects of sleep deprivation on students’ ability to solve problems. Ten participants went 8, 12, 16, 20, or 24 hours without sleep and then completed a set of simple addition problems. The number of addition errors was recorded.

Hours without sleep

8 8 12 12 16 16 20 20 24 24

Number of errors

8 6 6 10 8 14 14 12 16 12

a. Find the linear regression equation: y = _____________________ b. Interpret the slope and y-intercept for this data:

c. Find the correlation coefficient and interpret its meaning for this data: d. Predict the number of errors if a person went without sleep for 48 hours:

e. What domain makes sense for this data?

#2 This is the life expectancy at birth for males in the US for different years in the 20th century.

Year of birth

Male life expectancy (years)

1920 53.6

1925 56.3

1930 58.1

1935 59.4

1940 60.8

1945 62.8

1950 65.6

1955 66.2

1960 66.6

1965 66.8

1970 67.1

1975 68.8

1980 70.0

1985 71.2

1990 71.8

1995 72.5

1998 73.9

a. Find the linear regression equation: b. Interpret the slope and y-intercept for

this data: c. For what birth year does your equation

predict the life expectancy to reach 80 years?

d. Predict the life expectancy for a male

born in 1900: Is this interpolation or extrapolation?

e. Predict the life expectancy for a male born in 1982: Is this interpolation or extrapolation?

f. Are there any outliers for this data? g. Is a linear model a good fit for this data?

Why or why not?

Page 7: Honors Alg 2 Unit 2 Packet

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Honors Algebra II Notes

Unit 2 – Absolute Value Day 4

SOLVING AN ABSOLUTE VALUE EQUATION

Ex1: SOLVE | 2x – 4| = 12 ** We do not know if the “stuff” inside is a 12 or a -12!

So, we set up TWO possibilities!!!

2x – 4 = 12 OR 2x – 4 = -12 Solve each equation. Check your answers!

Set builder notation:

Ex2a: SOLVE |3x + 2| = 7 Ex2b: SOLVE 3|4w – 1| - 5 = 10

Set builder notation: Set builder notation:

Ex3a: SOLVE |2x + 5| = 3x + 4 Ex 3b: Solve for d: a|x + d| - c = b

Set builder notation: Set builder notation:

Extraneous Solutions: ____________________ Extraneous Solutions: ____________________

Ex4: Find a value for b such that |x| = x + b has exactly one solution.

SOLVING AN ABSOLUTE VALUE EQUATION IN THE CALCULATOR

** Almost all EQUATIONS can be SOLVED in the calculator, although some may be easier done

by hand!

STEPS:

Put the left side of the equation in y1

Put the right side of the equation in y2

The solution is where the two graphs intersect!

Move the cursor over the first intersection

Press “2nd

” “calc” and select option 5: intersect

Remember, we are usually solving for x, so write down the x value

Move the cursor over the second intersection

Press “2nd

” “calc” and select option 5: intersect

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Ex5: SOLVE 2|3x – 2| = 14 in the calculator by following the above steps.

Set builder notation: ______________________________

Ex6: SOLVE |x – 1| = 5x + 10 **these are the type that sometimes produce ________________

solutions… you don’t have to worry about that on the calc!

Set builder notation: ______________________________

SOLVING A SYSTEM

Review: When you are given TWO equations at the same time and told to solve, you are supposed to

find the x AND the y value(s) that work in both equations at the same time.

You can solve by graphing one equation in y1 and the other in y2 and finding BOTH the x and y values of

the intersections.

Ex7: SOLVE y = 2x + 4

y = |x + 2| - 3

We write our answer as the actual points of intersection: _______________________________

Ex8: SOLVE y = |x + 6|

y = -|x – 5|

Solution: _______________

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Honors Algebra II Name:

HW Day 4 Unit 2 Date: Period:

Absolute Value Equations

Write your answer in set builder notation.

1. |3p| = -12 2.

a 5

85

3. |m| + 2m = 11 4. -42 = -3|-x + 1|

5. 4|n + 8| = 56 6. |7m| + 3 = 73

7.

x

78 7

8. |k – 10| = 3

9.

51

3x 2 15 0

10. 2 ax c b 0

Solve the following systems.

11. y = 3x – 1 y = =|x| + 3 12. y = |4x – 7| y = -x + 8

Solution: Solution:

Source: Kuta Software

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UNIT 2 DAY 5 SOLVING ABSOLUTE VALUE INEQUALITIES NOTES

What is meant by |x| > 4? (x is more than 4 units from 0 on the number line)

The shaded arrows represent ALL of the numbers, x, that are more than 4 units away from 0.

We could also represent this graph by using TWO inequalities: ____________ OR __________

Ex1: SOLVE |3x + 6| > 12 **Set up TWO inequalities and solve each one.

3x + 6 > 12 OR 3x + 6 < -12

Set builder notation:

Ex2: SOLVE |2x – 3| ≥ 7

Set builder notation:

Ex3: SOLVE -2|x + 1| + 5 ≥ -3

Set builder notation:

What do you think is meant by |x| < 4?

What would that look like on a number line?

> / ≥ is read: ______________________

< / ≤ is read: ______________________

-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10

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4

2

-2

-4

-6

-5 5 10

Ex4: SOLVE -3|2x + 6| - 9 ≤ 15

Set builder notation:

Ex5: SOLVE for x: a|x – b| ≥ c

Set builder notation:

SOLVING AN ABSOLUTE VALUE INEQUALITY IN THE CALCULATOR

Ex6: Now SOLVE: |x – 5| ≥ 3 in the calculator. Sketch:

**If y1 = |x – 5| and y2 = 3, you are LOOKING to see where y1 is

greater (ABOVE) or EQUAL TO y2…

To find where they are EQUAL, find the intersections.

Set builder notation: ___________________

Ex7: SOLVE: |2x + 3| - 6 ≥ 7

Set builder notation: ___________________

Multiple Choice Practice:

Express the following as an absolute value inequality:

Ex 8: In a newspaper poll taken before an election, 42% of the people favor the incumbent mayor. The

margin of error for the actual percentage, p, is less than 4%.

A. |p – 0.42| < 0.04 B. |p – 0.04| < 0.42 C. |0.42 – p| > 0.04 D. |0.04 – p| < 0.04

Ex 9: For y = 3|7 – 2x| + 5, which set describes x when y < 8?

A. {x| 3 < x < 4} B. {x| 3 < x < 10} C. {x| x < 3 or x > 4} D. {x|x < 3 or x > 10}

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2

-2

-4

-6

-5 5 10

Honors Algebra II

Absolute Value Day 6 Notes

REVIEW: BASIC FUNCTION INFORMATION

What is a function?

How do you know if a graph is a function?

What is the DOMAIN?

What is the RANGE?

How do you find the x-intercept?

How do you find the y-intercept?

GRAPHING AN ABSOLUTE VALUE FUNCTION

Let’s look at the most basic absolute value function: f(x) = |x| which can also be written as:

What makes this look different from the EQUATIONS that we were SOLVING?

Ex1: GRAPH f(x) = |x| **We will make a TABLE of values

x y

** ALL ABSOLUTE VALUE GRAPHS ARE IN THE SHAPE OF A V!

**THE BOTTOM POINT OF THE GRAPH IS CALLED THE _________________.

What are the coordinates of the vertex? _____________

What is the DOMAIN of y = |x|? _______________________

What is the RANGE of y = |x|? ________________________

What are the intercepts of y = |x|? _________________________

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4

2

-2

-4

-6

-5 5 10

4

2

-2

-4

-6

-5 5 10

Ex2: GRAPH f(x) = |x| + 2.

What is the VERTEX of y = |x| + 2? ____________________

What is the DOMAIN of y = |x| + 2? _____________________

What is the RANGE of y = |x| + 2? _______________________

What are the INTERCEPTS of y = |x| + 2? ___________________

How does this graph compare to y = |x|?

Ex3: GRAPH f(x) = |x| - 3. How do you think this graph will compare to y = |x|?

What is the VERTEX of y = |x| - 3? ____________________

What is the DOMAIN of y = |x| - 3? _____________________

What is the RANGE of y = |x| - 3? _______________________

What are the INTERCEPTS of y = |x| - 3? ___________________

How does this graph compare to y = |x|?

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GRAPHING IN THE CALCULATOR

Ex4: GRAPH f(x) = |x - 5|.

press “y =”

press “catalog” and select “abs”

press “x – 5” and “)”

press “graph”

to see a table of values, press “2nd”

“graph”

What is the VERTEX of y = |x – 5|? ____________________

What is the DOMAIN of y = |x – 5|? ____________________

What is the RANGE of y = |x – 5|? ____________________

What are the INTERCEPTS of y = |x – 5|? ____________________

How does this graph compare to y = |x|? _____________________

Ex5: GRAPH f(x) = |x + 5|. How does this graph compare to f(x) = |x|? What is the vertex?

Ex6: GRAPH f(x) = |x – 3| + 7. How do you think this graph will compare to f(x) = |x|? What do you

think the vertex will be?

Ex7: GRAPH f(x) = -|x|. How does this graph compare to f(x) = |x|? How are the domain and range

affected?

Ex8: GRAPH f(x) = |4x| and g(x) = |x/4|.

Ex 9: At what x-coordinate does f(x) = |-2x + 3| - 2 have a minimum value?

A. -2 B. -2/3 C. 3/2 D. 3

SUMMARY: f(x) = |mx + b| + c

the value of m affects the “slope” of the graph

the value of b moves the graph left/right ( +b inside moves left, -b inside moves right)

the value of c moves the graph up/down (+ c moves up, - c moves down)

if there is a negative in the front, the whole graph is reflected over the x-axis.

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4

2

-2

-4

-6

-5 5 10

-5 5 10

4

2

-2

-4

-6

4

2

-2

-4

-6

-5 5 10

4

2

-2

-4

-6

-5 5 10

GRAPHING AN ABSOLUTE VALUE INEQUALITY

Ex1: GRAPH y ≤ |x – 4| + 5.

Where is the vertex?

What is the range?

Ex2: GRAPH –y + 3 > |x + 1|

Where is the vertex?

What are the intercepts?

**If you are given two INEQUALITIES at the same time, you need to graph on paper. The

overlapping shaded region is your solution.

Ex3: SOLVE y < |2x – 3|

y ≥ |x| + 2

Ex 4: Which function is graphed below?

A. y = |x| - 5

B. y = 5 - |x|

C. y = |-5x|

D. y = |5 – x|

What is the DOMAIN?

What is the RANGE?

What are the intercepts?

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Honors Algebra II Name: HW Day 6 Unit 2 Date: Period:

Graph each equation. Then find domain, range, intercepts, & the vertex.

1. y = |x – 1| 2. y = |x – 1| - 2

D: D:

R: R:

x = y = V: x = y = V:

3. y = |x + 3| + 3 4. y > |x – 2|

D: D:

R: R:

x = y = V: x = y = V:

5. y |x + 4| + 3 6. y < |x – 4| - 4

D: D:

R: R:

x = y = V: x = y = V:

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7. y = - |x – 2| - 2 8. y = - |x – 4|

D: D:

R: R:

x = y = V: x = y = V:

9. y -|x| + 4 10. y > - |x + 1| + 3

D: D:

R: R:

x = y = V: x = y = V:

11. y = -|x| + 2 12. Solve the system by graphing:

y < - |x + 1| - 1

y -5

D: D:

R: R:

x = y = V: x = y = V:

[Hint: Read the graph from left to right.]

Where is the graph increasing?

Where is the graph decreasing? Source: Kuta Software

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Honors Algebra 2 Unit 2 Day 9

Composition of Functions

REVIEW: FUNCTION NOTATION f(x) = 2x + 3 is the same thing as y = 2x + 3.

How do we read f(x)?

This essentially means that the function (and the y values of it) DEPENDS on the values of x.

What is meant by f(2)? How does this relate to graphing?

Find the following:

f(2) = ________

f(-3) = _______

f(0) = _______

f(c) = ______

CHALLENGES:

f(∆) = ______

f() = _____

f(+ ) = ______

f(k – 3) = _____

COMPOSITIONS

We will look at multiple functions at one time.

Ex 1: f(x) = -x + 4 and h(x) = 2x. Find the following:

f(h(3)) = ____________________

h(f(-5)) = ___________________

h(h(8)) = ___________________

** f(h(f(2))) = _________________

A Composition Function is the result of plugging one function into another like the last challenge

problem! Usually, though, the same variable is used.

Ex 2: f(x) = x2 + 2. Find:

f(x+1) =

The following example is the same concept, just presented in a different way!

Ex 3: f(x) = 3x + 5 and g(x) = x – 2. Find f(g(x)). What is g(x)?? So we really want to find:

f(x–2) =

NOTATION: f(g(x)) = f ◦ g(x) AND g(f(x)) = g ◦ f(x)

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Ex 4: f(x) = 2x2 and g(x) = x + 3. Find the following:

f(g(x)) = __________________________

f ◦ g(3) = ________________________

g ◦ f(x) = _________________________

g(f(-2)) = _________________________

g ◦ g(x) = _________________________

g ◦ g(7) = _________________________

FINDING THE DOMAIN AND RANGE OF COMPOSITIONS

Remember, Domain is: ________________ Range is: _________________

Ex 5: f(x) = x – 2 and h(x) = x2 – 1. Find the following:

Domain of f(x): _________________ Range of f(x): __________________

Domain of h(x): _________________ Range of h(x): _________________

f ◦ h(x) = ______________________

Domain of f ◦ h(x): _______________________ Range of f ◦ h(x): _______________

h ◦ f(x) = ______________________

Domain of h ◦ f(x): _______________________ Range of h ◦ f(x): _______________

** When finding the domain of a composition, you must consider the domain of each

of the separate functions!!

Ex 6: g(x) = x and h(x) = x2. Find the following:

Domain of h(x): ________________

Domain of g(x): ________________

h ◦ g(-3) = _________________________

h ◦ g(x) = _________________________

Domain of h ◦ g(x) = _________________________

Ex 7: Shirley is paid an annual salary plus a bonus of 4% of her sales over $15,000. Let x represent

Shirley’s sales, f(x) = x – 15,000 represent her sales over $15,000, and p(x) represent the amount of her

bonus. Which function notation represents the amount of her bonus?

A. f(x) + p(x) B. f(x) – p(x) C. f(p(x)) D. p(f(x))

Hint: What does her bonus DEPEND on?

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Unit 2 Day 9 HW

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2

-2

5 10

Honors Algebra 2 Unit 2 Day 10 Notes

Compositions and Inverses

FINDING THE INVERSE OF A FUNCTION (just the basics – used more later in the year)

Basically, an inverse is found by SWITCHING THE X AND Y. The resulting relation may

not be a function anymore!

Ex 1: Given { (1, -4), (-3, 2), (5, 2), (0, -7) } Is the given a function? Explain

a. Find the inverse.

b. Is the inverse a function? (Explain)

Ex 2: Given { (3, 4), (-4, 0), (-2, 1), (7, 5) } Is the given a function? Explain

a. Find the inverse.

b. Is the inverse a function? (Explain)

When a function’s inverse is also a function, it is said to be ___________________________.

Definition: A function is a one-to-one function if and only if each x and y value is used only

once.

When this is the case, the notation for the inverse is f -1

(x).

Why would we only use this notation for the inverses of one-to-one functions?

Recall: We use the _____________________ to visually determine if a graph is a function (so we can

see that for every x, there is only one y).

So, to visually determine if for every y there is only one x, we use the ______________________.

Ex 3: Using the function at the right, graph the inverse. Is the inverse

a function?

DOMAIN of the original: __________________

RANGE of the original: ___________________

DOMAIN of the inverse: __________________

RANGE of the inverse: ___________________

**NOTICE: sketch the line y = x on the graph at the right. What would happen if we folded our papers

on the line y = x? THIS IS ALWAYS THE CASE!

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A function and its inverse are reflections of each other over the line: ____________

Ex 4: In a) and b) are the graphs shown inverses of each other? Is the inverse a function?

a) DOMAIN of original: __________ b)

RANGE of original: ___________

DOMAIN of inverse: ___________

RANGE of inverse: ____________

What do you notice??

FINDING AN INVERSE ALGEBRAICALLY

We use the same general rule: SWITCH X AND Y! Then we will get y by itself.

Ex 5: f(x) = 3x – 2. Find the inverse. Ex 6: g(x) = x2 – 3. Find the inverse.

(Is it OK to use f -1

(x) notation?) (Is it OK to use g -1

(x) notation?)

Ex 7: Find the inverse of h(x) = -2x – 5

How can we make sure our answers are right?

The website below goes over multiple ways your calculator can confirm this for you!

http://www.mathbits.com/MathBits/TISection/Algebra2/inverse.htm

Step 1 Replace

g(x) with y

Step 2 Switch x

and y

Step 3 Solve for y

(get y by

itself)

Step 1 Replace f(x)

with y

Step 2 Switch x

and y

Step 3 Solve for y

(get y by

itself)

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USING COMPOSITIONS TO CONFIRM INVERSES

Recall: Multiplicative inverses are numbers that “cancel out” to a 1 when multiplied:

Such as, ½ × 2 = 1 or ¼ × 4 = 1.

Additive inverses are numbers that “cancel out” to a 0 when added: such as -3 + 3 = 0

Functional inverses are numbers that “cancel out” to an x when composed together!

Given f(x) and f -1

(x), then f ◦ f -1

(x) = x = f –1

◦ f(x) (You must do both confirm)

So, plugging an inverse into its original function basically cancels everything out and you are left with

just x!

Ex 8: Use compositions to determine whether the following are inverses.

a) f(x) = 4x – 3 and g(x) = (x + 3)/4 b) f(x) = 6x – 1 and g(x) = (x – 1)/6

f ◦ g(x) = g ◦ f(x) = f ◦ g(x) = g ◦ f(x) =

Ex 9: Find h(h-1

(256)) Ex 10: Find h-1

◦ h(-457838)

Ex 11: Can you think of a more time-effective way to do a problem like example 8?

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Unit 2 HW Day 10 -11

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Linear Word Problems Name ________________

Honors Algebra 2 Unit 2 Day 12 Notes

Review Translating Words to Math:

Problem: Jeanne has $17 in her piggy bank. How much money does she need to buy a game that costs $68?

Solution: Let x represent the amount of money Jeanne needs. Then the following equation can represent this problem:

17 + x = 68

We can subtract 17 from both sides of the equation to find the value of x.

68 - 17 = x

Answer: x = 51, so Jeanne needs $51 to buy the game.

In the problem above, x is a variable. The symbols 17 + x = 68 form an algebraic equation. Let's look at

some examples of writing algebraic equations.

Example 2: Write each sentence as an algebraic equation.

Sentence Algebraic Equation

Twice a number, decreased by twenty-nine, is seven.

Thirty-two is twice a number increased by eight.

The quotient of fifty and five more than a number is ten.

Twelve is sixteen less than four times a number.

Example 3: Write each sentence as an algebraic equation.

Sentence Algebraic Equation

Eleni is x years old. In thirteen years she will be twenty-four years old.

Each piece of candy costs 25 cents. The price of h pieces of candy is $2.00.

Suzanne made a withdrawal of d dollars from her savings account. Her old balance was $350, and her new balance is $280.

A large pizza pie with 15 slices is shared among p students so that each student's share is 3 slices.

Example 1: Write each sentence as an algebraic equation.

Sentence Algebraic Equation

A number increased by nine is fifteen.

Twice a number is eighteen.

Four less than a number is twenty.

A number divided by six is eight.

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Word Problem Practice:

Example 1.

Example 2:

Example 3:

Example 4:

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Honors Algebra 2 Name ________________

Function and Lines Word Problems Homework Unit 2 Day 12

SHOW WORK!!!!

1.

2.

3.

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