EXPLORING QUADRATIC FUNCTIONS/INEQUALITIES By: Michele Markle
Course/ Grade Level: Math B/ Grade 11 Time SPAN:
42 minute class periods
Tools:
ti 83 Plus calculator Overhead projector with TI 83 Plus adapter Graph paper Course III Amsco 3rd edition textbook Worksheets
DESCRIPTION OF RESOURCES USED
Amsco, Course III Integrated Mathematics, Third Edition, Edward P. Keenan and Ann Xavier Gantert, Chapter 13, pages 659-677, copyright 2000. Examgen computer program I2T2 Worksheet, page 27, Warm Up 27. Old New York State Math B Exam questions
Quadratic Functions/Inequalities
COURSE III –
MATH B Lesson
Objectives
Assignments
Identify key info. Represented by min, max, zeros,
1
connect relation of x & y Determine window on calculator Find solutions, min, max using calculator for
Worksheet
2
quadratic functions
Worksheet Even numbers
3
Sketch Graphs Solve Systems of Equations
Worksheet
4
Review Discriminant Sum & Product of Roots
Finish Review
5
Solve Quadratic Inequalities
Worksheet
6
Applications
Worksheet
7
UNIT TEST
STANDARDS USED New York State Learning Standards: Standard 1: Analysis, Inquiry, and Design Standard 2: Information Systems Standard 3: Mathematics Standard 7: Interdisciplinary Problem Solving
NCTM Learning Standards: Numbers and Operations Algebra Problem Solving Communication Connections Representation
DESCRIPTION OF MATERIALS AND EQUIPMENT NEEDED Day One:
Each student needs their TI-83 Plus calculators Overhead and TI-83 Plus overhead unit Quadratic Function Worksheets Review Worksheet for group work Homework Assignment
Day Three: Day Four: Day Five: Day Six:
Each student needs their TI-83 Plus calculators Overhead and TI-83 Plus overhead unit Warm up worksheet on previous days work Previous night’s homework assignment Worksheet – Finding the Roots of an Equation Worksheet – Finding the Min. or Max Review Worksheet for group work
Day Two:
Each student needs their TI-83 Plus calculators Overhead and TI-83 Plus overhead unit Warm up worksheet on previous days work Previous night’s homework assignment Graph Paper Amsco Course III Textbook Worksheet - Solving Systems of Equations Review Worksheet for group work Each student needs their TI-83 Plus calculators Overhead and TI-83 Plus overhead unit Warm up worksheet on previous days work Previous night’s homework assignment Amsco Course III Textbook Review Worksheet for group work Each student needs their TI-83 Plus calculators Overhead and TI-83 Plus overhead unit Warm up worksheet on previous days work Previous night’s homework assignment Amsco Course III Textbook Worksheet – Quadratic Inequalities Review Worksheet for group work Each student needs their TI-83 Plus calculators Overhead and TI-83 Plus overhead unit Warm up worksheet on previous days work Previous night’s homework assignment Applications Worksheet
OVERVIEW OF ENTIRE UNIT Day One: Transform an application to calculator language to be modeled (graphed) Discuss independent and dependent variables Discuss maximum and minimum Demonstrate finding minimum and maximums on calculator Find maximum and minimum of real life applications Assignment of finding dependent/independent variables, max and min, zero, and window settings Group work on review topics Day Two: Use calculator to find critical values in a quadratic function Calculator instruction on finding min, max, roots solutions of quadratic functions Describe relationships of quadratic function graphs Guided Practice on finding roots Assignment on finding roots of an equation and finding min, and max Group work on review topics Day Three: Sketching graphs on paper and calculator and solving system of Equations Discussion on what information is needed to sketch quadratic functions Guided practice on sketching graphs on paper and calculator Discussion on solving system of equations graphically Guided practice on sketching systems of equations on graph paper and calculator Assignment on graphing quadratic functions and system of equations Group work on review topics Day Four: Review discriminant and nature of roots and sum and product of roots Discussion on quadratic formula and discriminant Guided practice on quadratic formula and discriminant Description of nature of roots Looking at ways to find sum and product of roots Assignment is to finish review topic worksheet Day Five: Solving an inequality and graphing it on a number line Instruction on solving quadratic inequalities – by hand and by calculator Guided practice on solving quadratic inequalities Assignment on graphing inequalities Group work on review topics Day Six: Applying quadratic inequalities to real life situations Group work on applications regarding quadratic functions No assignment Test Prep due on test day
Lesson Plan – Day One Quadratic Functions/Inequalities
Class: Course III – Math B Anticipatory Set: Hand out and explain test prep which is due the day of the test.
Objectives:
Identify key information represented by min., max, and zeros Connect relation of x and y Determine windows on calculator
Materials:
Each student needs their TI-83 Plus calculators, Overhead and TI-83 Plus overhead unit, Quadratic Function Worksheets, Review Worksheet for group work, Homework Assignment
Procedures: 20 minutes – Calculator Instruction (see worksheet) Explain Independent/Dependent Variables Explain Maximum and Minimum 10 Minutes-
Guided Practice – Using Calculator
10 Minutes-
Group Work to hand in (See review sheet)
Good Questions to Check for Understanding: How can we estimate the max and min? Can we use the axis of symmetry to help us?
Closure: it.
Ask if there are any questions, hand out homework and explain
Homework: Quadratic Functions worksheet
Adjustments for next time:
Quadratic Functions
A function is a relation between two variables
X- Min:
The lowest point for _———————————— variable
X-Max:
The highest point for —————————————variable
Y Min:
The lowest point for ______________ variable
Y Max:
The highest point for _____________ variable
THESE NEED TO BE SET SO THE WHOLE MODEL (graph) CAN BE SEEN (PERTINENT).
KEY
Quadratic Functions
A fonction is a relation between two variables
negative Positive
X- Min:
The lowest point for _—Independent—— variable
X-Max:
The highest point for —Independent———variable
Y Min:
The lowest point for __Dependent___ variable
Y Max:
The highest point for ___Dependent_ variable
THESE NEED TO BE SET SO THE WHOLE MODEL (graph) CAN BE SEEN (PERTINENT).
Quadratic Functions For the following situations name the dependent and independent variables. Determine whether the model (graph) of the situation will have a maximum or a minimum. Determine what the zero between the first and fourth quadrants represents. Determine what window settings your calculator will need to see the whole graph. The height in feet of a rock thrown upward at an initial speed of 64 ft/sec from a cliff 50 ft. above the ocean beach is given by the function s(t) = -16t 2 + 64t + 50, where t is the time in seconds. Find the maximum height above the beach that the rock will attain. Dependent variable: ________________ Independent Variable: Max or Min: ______ Zero: _____ Window Settings: x min: ___ x max: __ y min: ___ y max:___ The height in feet of a ball thrown upward at an initial speed of 80 ft/sec from a platform 50 ft. high is given by the function s(t) = - 16t2 +80t + 50., where t is the time in seconds. Find the maximum height above the ground that the ball will attain. Dependent variable: ________________ Independent Variable: Max or Min: ______ Zero: _____ Window Settings: x min: ___ x max: __ y min: ___ y max:____ A manufacturer of a camera lenses estimated that the average monthly cost (C) of a lens if given by the function C(x) = 0.1 x2 - 20x + 2000, where x is the number of lenses produced each month. Find the number of lenses the company should product in order to minimize the average cost. Dependent variable: ________________ Independent Variable: _______________ Max or Min: _______ Zero:_______ Window Settings: x min:______ x max:______y min:______ y max:_____ A pool is treated with a chemical to reduce the amount of algae. The amount of algae in the pool t days after the treatment can be approximated by the function A(t) = 40t2 – 400t + 500. How many days after treatment will the pool have the least amount of algae? Dependent variable: ________________ Independent Variable: _______________ Max or Min: _______ Zero:_______ Window Settings: x min:______ x max:______y min:______ y max:_____
Go into y = and put the above equation in. Go to windows and decide what the x min, x max, y min, y max should be. How do you decide this? Well look at the last number – this is going to be your y-intercept so try going above that number for the y-max and leave the others.
Now go to graph to see if you can see the whole picture.
You can’t so decide where you need to go. You need to go further up on the y axis to see the turning point so make the y max larger. (hint: you could have found the axis of symmetry and gone to the table to find the y value and used that as your y max.( a little above it).
Key to the rest of the problems: Quadratic Functions For the following situations name the dependent and independent variables. Determine whether the model (graph) of the situation will have a maximum or a minimum. Determine what the zero between the first and fourth quadrants represents. Determine what window settings your calculator will need to see the whole graph. The height in feet of a rock thrown upward at an initial speed of 64 ft/sec from a cliff 50 ft. above the ocean beach is given by the function s(t) = -16t 2 + 64t + 50, where t is the time in seconds. Find the maximum height above the beach that the rock will attain. 114 ft Dependent variable: ___height s(t)_____________ Independent Variable: Speed (t) Max or Min: _Max_____ Zero:Where the rock hits the ocean Window Settings: x min: -10_ x max: 10__ y min: -10___ y max:__150_ The height in feet of a ball thrown upward at an initial speed of 80 ft/sec from a platform 50 ft. high is given by the function s(t) = - 16t2 +80t + 50., where t is the time in seconds. Find the maximum height above the ground that the ball will attain. 150 ft Dependent variable: ____height s(t)____________ Independent Variable: Speed (t) Max or Min: _Max_____ Zero: Where ball hits the platform_____ Window Settings: x min: -10___ x max: 10__ y min: -10___ y max:_250___
A manufacturer of a camera lenses estimated that the average monthly cost (C) of a lens if given by the function C(x) = 0.1 x2 - 20x + 2000, where x is the number of lenses produced each month. Find the number of lenses the company should product in order to minimize the average cost. 100 lenses Dependent variable: ___cost c(x)_____________ Independent Variable: ___# produced per month (x)_ Max or Min: __Min_____ Zero:__none_____ Window Settings: x min:_-10_____ x max:_200_____y min:_-1000_____ y max:_2210____
A pool is treated with a chemical to reduce the amount of algae. The amount of algae in the pool t days after the treatment can be approximated by the function A(t) = 40t2 – 400t + 500. How many days after treatment will the pool have the least amount of algae? Dependent variable: ___amount of algae A(t)___ Independent Variable: ___Days (t)_________ Max or Min: __Min_____ Zero:__where there is no algae____ Window Settings: x min:_-10_____ x max:__200 y min:__-10____ y max:_2000____
REVIEW GROUP WORK ANSWER KEY: 1) Find the inverse for: {(8,5), (6,8), (4,11), (2,14)} 2) Find the inverse for: y = 4x + 7
y=
{(5,8), (8,6), (11,4), (14,2)}
x!7 4
3) f(x) = x2 – 2x – 3; g(x) = x-1 what is (g(f(x)) x2 –2x – 4 4) g(x) = -2x3 – 5x2 + 4x –3 domain: -3 ≤ x ≤ 5 what is the largest value for the range? -108 5) g(x) = 3-2x does (1,-2) appear on its graph? NO
REVIEW GROUP WORK
1) Find the inverse for: {(8,5), (6,8), (4,11), (2,14)} 2) Find the inverse for: y = 4x + 7 3) f(x) = x2 – 2x – 3; g(x) = x-1 what is (g(f(x)) 4) g(x) = -2x3 – 5x2 + 4x –3 domain: -3 ≤ x ≤ 5 what is the largest value for the range? 5) g(x) = 3-2x does (1,-2) appear on its graph?
HOMEWORK- DAY ONE Quadratic Functions For the following situations name the dependent and independent variables. Determine whether the model (graph) of the situation will have a maximum or a minimum. Determine what the zero between the first and fourth quadrants represents. Determine what window settings your calculator will need to see the whole graph.
The suspension cable that supports a small foot bridge hands in the shape of a parabola. The height in feet (h) of the cable above the bridge is given by the function h(x) = 0.025x2 - 0.8x + 25, where x is the distance in feet from one end of the bridge. What is the minimum height of the cable above the bridge? Dependent variable: ________________ Independent Variable: Max or Min: ________ Zero: ___________ Window Settings: x min: ___
x max: __ y min: ___ y max:
The net annual income of a family physician can be modeled by l(x) = - 290(x - 48)2 + 148,000, where x is the age of the physician and 27 < x < 70. Find the age at which the physician's income will be a maximum. What is the physician's maximum income? Dependent variable: ________________ Independent Variable: Max or Min: ________ Zero: ___________ Window Settings: x min: ___ x max: __ y min: ___ y max: Karen is throwing an orange to her brother Jim, who is standing on the balcony of their home. The height, h (in feet), of the orange above the ground t seconds after it is thrown is given by h(t) = - 16t 2 + 32t + 4. If Jim's outstretched arms are 18 ft. above the ground, will the orange ever be high enough so that he can catch it? Dependent variable: ________________ Independent Variable:________________
Max or Min: ________________ Zero:____________________ Window settings: x min__________ x max____________ y min_____________ y max_____
Some football fields are built in a parabolic mound shape so that water will drain off the field. A model for the shape of the field is given by h(x) = -0.00023475x2 + 0.0375x, where h is the height of the field in feet at a distance of x feet from the sideline. What is the maximum height? Round to the nearest tenth. Dependent variable: ________________ Independent Variable: _______________ Max or Min: ______ Zero: ______________ Window Settings: x min: ___ x max: __ y min: ___ y max: ______ The Buningham Fountain in Chicago shoots water from a nozzle at the base of the fountain. The height, h (in feet), of the water above the ground t seconds after it leaves the nozzle is given by h(t) = - 16t2 + 90t •»• 15. What is the maximum height of the water spout to the nearest tenth of a foot? Dependent variable: _____________________ Independent Variable: _____ Max or Min: __________ Zero:
_________
Window Settings: x min: ___ x max: __ y min: ___ y max: On wet concrete, the stopping distance, s (in feet), of a car traveling v miles per hour is given by s(v) = 0.055v2 + 1.1v. At what speed could a car be traveling and still stop at a stop sign 44 ft away? Dependent variable: _________________________ Independent Variable: _______________ Max or Min: __________ Zero: _________ Window Settings: x min: _____ x max: __ y min: __
y max;______
'"N
HOMEWORK- DAY ONE KEY Quadratic Functions For the following situations name the dependent and independent variables. Determine whether the model (graph) of the situation will have a maximum or a minimum. Determine what the zero between the first and fourth quadrants represents. Determine what window settings your calculator will need to see the whole graph.
The suspension cable that supports a small foot bridge hands in the shape of a parabola. The height in feet (h) of the cable above the bridge is given by the function h(x) = 0.025x2 - 0.8x + 25, where x is the distance in feet from one end of the bridge. What is the minimum height of the cable above the bridge?18.6 Dependent variable: _height(h)_______________ Independent Variable: Distance (x) Max or Min: __Min Zero: __None – cable on the ground Window Settings: x min: -10___
x max: _30_ y min: -10___ y max:25
The net annual income of a family physician can be modeled by I(x) = - 290(x - 48)2 + 148,000, where x is the age of the physician and 27 < x < 70. Find the age at which the physician's income will be a maximum. What is the physician's maximum income? 48 years old Dependent variable: ____net annual income__ Independent Variable: age of the physician Max or Min: _max_______ Zero: __income is at 0_________ Window Settings: x min: _27__ x max: 70__ y min: _-10__ y max:150000 Karen is throwing an orange to her brother Jim, who is standing on the balcony of their home. The height, h (in feet), of the orange above the ground t seconds after it is thrown is given by h(t) = - 16t 2 + 32t + 4. If Jim's outstretched arms are 18 ft. above the ground, will the orange ever be high enough so that he can catch it? Yes because the orange will reach a max of 20 ft. Dependent variable: ___height h(t)_____________ Independent Variable:____seconds (t)____________
Max or Min: ___max_____________
Zero: where the orange hits the ground Window settings: x min___-10_______ x max__10___ y min___-10___ y max__30___
Some football fields are built in a parabolic mound shape so that water will drain off the field. A model for the shape of the field is given by h(x) = 0.00023475x 2 + 0.0375x, where h is the height of the field in feet at a distance of x feet from the sideline. What is the maximum height? Round to the nearest tenth. 1.5 ft Dependent variable: __Height h(x)______________ Independent Variable: __feet from the side line (x)___ Max or Min: __max____ Zero: ___where the field is at water level_ Window Settings: x min: -80___ x max: 200__ y min: -10___ y max: _10_____ The Buningham Fountain in Chicago shoots water from a nozzle at the base of the fountain. The height, h (in feet), of the water above the ground t seconds after it leaves the nozzle is given by h(t) = - 16t2 + 90t + 15. What is the maximum height of the water spout to the nearest tenth of a foot? 141.56 ft Dependent variable: _____height h(t)________________ Independent Variable: ___seconds (t)__ Max or Min: __Max________ Zero:
__Water hits ground_______
Window Settings: x min: _-10__ x max: 10__ y min: -10___ y max:145 On wet concrete, the stopping distance, s (in feet), of a car traveling v miles per hour is given by s(v) = 0.055v2 + 1.1v. At what speed could a car be traveling and still stop at a stop sign 44 ft away? 154.88 mph Dependent variable: _____Stopping distance S(v)____________________ Independent Variable: __MPH (v)_____________ Max or Min: __min________ Zero: ___Stopping distance is at 0______ Window Settings: x min: _-30____ x max: _10_ y min: _-10_
y max;__10____
Lesson Plan – Day Two Quadratic Functions/Inequalities
Class: Course III – Math B Anticipatory Set: 3 minute warm-up and go over previous night’s homework
Objectives:
Use calculator to find critical values in a quadratic function
Materials:
Each student needs their TI-83 Plus calculators, Overhead and TI-83 Plus overhead unit, Warm up worksheet on previous days work, Previous night’s homework assignment, Worksheet – Finding the Roots of an Equation, Worksheet – Finding the Min. or Max, Review Worksheet for group work
Procedures: 10 minutes – Go over Homework and complete warm-up 10 minutes – Calculator Instruction – (give steps) Finding Min, Max, Roots, solutions of quadratics 10 minutes – Guided Practice using calculator to find the roots 10 minutes - Review Group work and hand out homework
Good Questions to Check for Understanding: What does zero mean? What does root mean? Where do we find roots? Describe relationships of quadratic function graphs.
Closure: it.
Ask if there are any questions, hand out homework and explain
Homework: Finding min and max and roots worksheets
Adjustments for next time:
Warm – up
Course III – Math B
Name ________________________ Date__________________________________ A pool is treated with a chemical to reduce the amount of algae. The amount of algae in the pool t days after the treatment can be approximated by the function A(t) = 40t2 – 400 t + 500. How many days after treatment will the pool have the least amount of algae? Dependent variable: _________________________ Independent variable:________________________ Max or Min: _________________________ Zero: ________________________ Window Settings: x min:_________x max:
___ y min: ________ y max: ____________
Warm – up
Course III – Math B
Name _KEY_______________________ Date__________________________________ A pool is treated with a chemical to reduce the amount of algae. The amount of algae in the pool t days after the treatment can be approximated by the function A(t) = 40t2 – 400 t + 500. How many days after treatment will the pool have the least amount of algae? 5 days Dependent variable: ____amount of algae A(t)_____________________ Independent variable:______days (t)__________________ Max or Min: ____Min._____________________ Zero: ____Where there is no algae____________________ Window Settings: x min:___-10____ x max: 10 y min: __-500__ y max: ____10____
Notes: The place where the graph of a quadratic equation intersects the x-axis is called its solutions or roots. When a graph doesn’t cross the x-axis, it is said to have complex or imaginary roots. Practice solving equations using factoring and quadratic formula first:
3x2 +7x +2 = 0 (3x+1) (x + 2) = 0 3x+1 = 0 x+2 = 0 3x = -1 x = -2 x = -1/3
{-1/3, -2} therefore, the graph intersects the x-axis at –1/3 and –2.
3x2 = 2(x+2) 3x2 = 2x + 4 3x2 - 2x – 4=0 need to use quadratic formula: ! b ± b 2 ! 4ac x= 2a
2 ± 4 ! 4(3)( !4) 1 52 = ± 6 3 6 x= 1.54, -.869 therefore, the graph intersects the x-axis at 1.54 and -.869 x=
Finding solutions (roots) using the calculator: 1.Press Y= and CLEAR to clear the Y1 prompt. Press ∇ and CLEAR to clear additional prompts. 2. Set the equation to zero. Enter your equation for y1. For example, enter 3x2 –2 = 0 for y1 by pressing 3 X,T,θ,n x2 -2 ENTER. Press ZOOM 4 to view the equation in the decimal window. 3. Find where the equation is equal to zero by pressing 2nd CALC 2 (zero), set the lower bound for the calculation by moving the cursor to the left (above in this case) of the left zero by pressing β and then press ENTER. Set the upper bound for the calculation by Pressing α to move the cursor to the right (below in this case) of the zero and press ENTER ENTER. An accurate approximate for the left zero will appear at the bottom of the screen. Repeat for the right zero.
What does the zeros mean in a quadratic function? Ex) The height of an object is given by the function: h(t) = -16x2 + 4x + 52. Find the zero and tell me what it means? X = 1.9 and at 1.9 sec. After release the object has 0 height or hits the ground (or water)
Describe relationships of a quadratic graph. H(t) H (height is a function of the time passed) o Every point on the graph is (x,y) x = time, y = height (t)
When will an equation have a minimum value (from yesterday)? When the a-term is positive. When will an equation have a maximum value (from yesterday)?When the a-term is negative. The max. of a quadratic function that is a relationship between height & time is the time from the start(x=0 is the starting time) when the object reaches its max. height. Will this type of function have a negative or positive a – term? Negative Using the calculator to find min or max. 1. Enter the function and graph it as taught from yesterday. Use the example above.
2. Press 2nd calc.
3. Select Maximum for our example 4. Follow prompts on screen. GO to the left of the curve, then right and then a guess (similar to finding zeros)
Have the students try a few of finding roots and min and max. Same sheet as their homework. Use same sheet that says finding roots for finding min and max .If time permits do a couple of group work problems as well.
Answer Key to Finding the roots and min and max. 3. Roots: None Min. (1,2)
4. Roots: {-4,1} Min.(1-1.5,-6.3)
5. Roots: None Max: (1,-1)
6. Roots: {-9,-2.4} Max: (-.8,5.1)
7. Roots: {-2,0} Min: (-1,-2)
8.Roots: {-1.5,0) Max: (-.8,1.1)
9. Roots: None Max: (1,-3)
10. Roots: None Max: (.2,-5.9)
11. Roots {-2.9,1.4} Min: (-.8,-9.1)
12. Roots: {-2,1} Max: (-.5,2.3)
13. Roots: {-1.5,.5} Min: (-.5,-2.75)
14.Roots: {.7,4.3} Min: (2.5,-3.25)
15. Roots: None Min: (.7,-.7)
16. Roots: {-2.7,.2} Max: (-1.25,4.125)
17. Roots: {-.7} Min: (-.8,-.1) 23. 18.6 Feet 26 1.5 feet
Key to group review 1a. {(9,2), (5,4), (8,13), (-10,-1)} 2a. y =
5x + 30 2
3a. 0 4a. –5x2 +82 5a. x >2 or x < -2 5b. all real numbers except 2
Lesson Plan – Day Three Quadratic Functions/Inequalities
Class: Course III – Math B Anticipatory Set: Go over previous day’s homework and complete warm-up
Objectives:
Sketch given graphs on paper given information from the calculator Solve systems of equations with quadratics
Materials:
Each student needs their TI-83 Plus calculators, Overhead and TI-83 Plus overhead unit, Warm up worksheet on previous days work, Previous night’s homework assignment, Graph Paper, Amsco Course III Textbook, Worksheet - Solving Systems of Equations ,Review Worksheet for group work
Procedures: 10 min – go over homework and complete warm-up 5 min – Instruction in graphing neat graphs 5 min – Guided Practice drawing graphs 5 min – Solving Systems of Equations 10 min – Guided Practice solving Systems of Equations p.670-671 #2,10,14,15,16 5 min – Group work
Good Questions to Check for Understanding: Can anyone describe the procedure of graphing and solving systems of equations? How do you know your solutions are correct?
Closure:
Ask if there are any questions, hand out homework and explain it.
Homework: Graphing and Solving Systems of Equations Worksheet
Adjustments for next time:
Course III – Math B
Warm-Up Find the roots of each equation by using the quadratic formula and check. 1. 2x2 +5 = 11x
2. x (x+4) =1
Answer key to warm- up
1. {5, .5}
2. x =
!5± 2 5 !5 or ± 5 or { .24,-4.24} 2 2
Go through p. 670 showing how to graph and then how to solve the systems of equations. 2. What does it mean if the two graphs of a system do not intersect? No solutions 10. y = -x2 +4 and y = x + 2
[ students already know how to graph the line so just review this]
Step 1: Using calculator graph the first equation
Step 2: We will now graph it on graph paper [you need at least 7 points so go to 2nd graph to see the table.
Find where the turning point is [ # where 3 above it and 3 below it are identical]. These are the points you will graph on your paper. Plot (-3,-5), (-2,6), (-1,3),(0,4) and so forth Step 3: ALWAYS LABEL YOUR GRAPH WITH THE ORIGINAL EQUATION. Step4: Now do you recall how to graph a line? What is your y-intercept? 2 What is your slope?1 Start at (0,2) and go up 1 to right 1 and draw a line and label it. (You can also put it in your calculator and go to the table at plot points that way)
Step 5: We need the solutions. So press 2nd Trace 5: Intersect
Place cursor on first curve, ENTER, place cursor on 2nd curve (2nd equation), ENTER, then place cursor where you think they intersect (guess)
You now have one solution (-2,0)Now do the same thing on the other side of your graph.
Second solution is (1,3) Step 6: Always substitute the numbers back in and check your solutions. You can also check the table if both the y values are the same that is your solution
Have students try # 14 and #15 Answers should be: y=2-x2 and y = 2x + 4
14)
NO solutions
x2 + y2 = 16 and x-y=4
15)
(0,-4) and (4,0)
xy = -6 and x+3y = 3
16)
(-3,2) and (6,-1)
If time you could have them do more practice problems from the Amsco book.
Homework – Day Three Course III – Math B
Solve the following systems of equations using any method you would like. Draw the graph on graph paper when indicated. 1)
2)
3)x2+y2=8
Draw these graphs: 4) y = x2 –3 2x + y = -2
x+y = 4
5) x2 + y 2 = 16 x–y=4
KEY TO HOMEWORK – DAY THREE 1.
solution: ( 1,0)
solution: ( 4,3)
2.
Solution: ( -4,-2)
3.
Solution: (2,4)
Solution: Solution:
Solution: (2,2)
4.
Solution: (.414,-2.82)
Solution: (-2.414,2.83) Or (-1 ± 2 , ± 2 2 )
5.
Solution (4,0) and (0,-4)
Group Work
1. What are the domain and range of the function pictured below?
2. Give h(x) =
x !5
a. Find the domain and range of h(x)
b. Is h(x) a one to one function? Why?
3. Which of the following would represent a number whose distance from 7 is 6 units?
a) x – 7 = 6
b) |x-7|=6
c) x-6 = 7
d) |x-6|=7
4. The average age of a student in Juanita’s class is 16 years old. However, the difference between a student’s age, ‘a’, and the average age 16, is half a year. Write an equation using absolute value that could be used to represent this information.
ANSWER KEY TO GROUP WORK
1. domain: { -8 ≤ x < 7}
2. Domain: x ≥ 5 b. Yes 3. b 4. |a-16| = ½
Range: {-8 ≤ y < 4}
Range: y > 0
Lesson Plan – Day Four Quadratic Functions/Inequalities
Class: Course III – Math B Anticipatory Set: Go over previous day’s homework and complete warm-up
Objectives:
Review using the value of discriminant to determine the Nature of the Roots Review finding the sum and product of roots; given a quadratic equation
Materials:
Each student needs their TI-83 Plus calculators, Overhead and TI-83 Plus overhead unit, Warm up worksheet on previous days work, Previous night’s homework assignment, Amsco Course III Textbook, Review Worksheet for group work
Procedures: 10 min – go over homework and complete warm-up 5 min – Review Discriminant, Nature of Roots 5 min – Guided Practice p. 659 #2-12 even 5 min – Review Product and Sum of Roots 5 min – Guided Practice p. 666 #4-12 even 10 min – Guided Practice on Function Applications
Good Questions to Check for Understanding: When asked to state the number of and nature of roots you will use what? What is the formula for finding the sum of the roots and the product of the roots?
Closure:
Ask if there are any questions, hand out homework and explain it.
Homework: Group worksheet
Adjustments for next time:
Course III – Math B Warm-Up
What are the zeros for the following equations: 1. f(x) = x3 + 2x2 -1
2. f(x) = x2 + 10x + 18
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Answers to warm – up
What are the zeros for the following equations: 1. f(x)=x3 + 2x2 –1
Solutions: x = -1 and .6180
2. f(x) = x2 + 10x + 18
Solutions: x = -7.6 and –2.35
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Go through and solve x2 – 8x + 17 = 0 with the quadratic formula You get 4±i which means the roots are imaginary and conjugates For information about the roots of a quadratic equation: we can use the discriminant: b2 – 4ac
b2 – 4ac > 0 and a perfect square the roots are real, rational and unequal b2 – 4ac > 0 and not a perfect square the roots are real, irrational and equal b2 – 4ac = 0 the roots are real, rational, and equal b2 – 4ac < 0 the roots are imaginary Give examples of each. 1. x2 – 2x – 3 = 0 16 so real rational and unequal 2. x2 – 4x +4 = 0 0 so real, rational and equal 3. x2 – 4x +5 = 0 -4 so imaginary
Students try: 1. 2x2 +6x + 3 = 0
Real, Irrational and unequal
2. x2 + 3x – 5 = 0
Imaginary
3. x2 +3x +4 = 0
Imaginary
4. x2 – 10x +25 = 0
Real, rational and equal
Look at the graphs as well and have them describe what they see. Find the value(s) of K for which the given equation has one real double root. 4. 1) x2 +6x +k = 0 b2 – 4ac = 0 36 – 4k = 0 -4k = -36
k=9
check: x2 +6x– 2x +9 = 0 (x+3)(x+3) = 0 x = -3 39
Guided Practice : p . 659 #2- 12 even They have to evaluate the discriminant and tell the nature of roots. 2. x2 +3x – 10 = 0
real, rational, unequal
4. x2 –10x + 25 = 0
real, rational, equal
6. x2 + 7x – 30 = 0
real, rational, unequal
8. 2x2 +3x = 4
real, irrational, unequal
10. x2 +9 = 2x2 +x
real, irrational, unequal
12.
x2 +6 = 3x2 + x
real, rational, unequal
Now, talk about finding the sum and the product of the roots. !b a c r1 • r2 = a
r1 + r2 =
Try: Find the sum and product. 1) x2 – 2x -15 = 0 2/1 = sum -15 * 1 = product 2) 2x2 = 3x – 6 2x2 – 3x + 6 = 0 sum: 3/2 Product: 3 Have them try p. 666 # 4-12 even 4. 4x2 + x – 3= 0
sum: -1/4
6. 3x2 +9x = 2
Sum: -3
Product: -2/3
8. x2 +9 = 0
Sum: 0
Product: 9
10. 2m2 +2 = 5m
Sum: 5/2
Product:1
12. y2 +2y = 2
Sum: -2
Product: -2
Product: -3/4
Give them group work: 40
Group work:
In 1-10, determine if each of the following relations is a function or not. Explain your answer. If the relation is a function, state its domain and range. 1. {(6, 3), (5, 8), (2, 7)} 2. {(5, 4), (5, 5), (5, 6)}
5.
3. {(1, 2), (2, 2), (3, 2)}
4. y
6.
7. Given: f(x) as shown in the accompanying diagram.
Find: a. f(2) b. x such that f(x) = 2 c. f-1 (2) d. the element in the domain that corresponds to 0 in the range
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Answer key to group work: 1) 2) 3) 4) 5) 6) 7)
yes, domain: {(6,5,2)} Range: {(3,8,7)} not a function yes domain: {(1,2,3)} Range: {(2,2,2)} Not a function Not a function Not a function a. 9 b. x = 1 c. 1 d. 1.5
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Lesson Plan – Day Five Quadratic Functions/Inequalities
Class: Course III – Math B Anticipatory Set: Go over previous day’s homework and complete warm-up
Objectives:
Solve an inequality and graph on a number line
Materials: Each student needs their TI-83 Plus calculators, Overhead and TI-83 Plus overhead unit, Warm up worksheet on previous days work, Previous night’s homework assignment, Amsco Course III Textbook, Worksheet – Quadratic Inequalities, Review Worksheet for group work
Procedures: 10 min – go over homework and complete warm-up 10 min – Instruction on solving quadratic inequalities 10 min – Guided Practice – p. 677 #10-20 even, p. 264 #1,3,9,10,13,16 10 min. Functions Chapter Review
Good Questions to Check for Understanding: What does critical value mean?
Closure:
Ask if there are any questions, hand out homework and explain it.
Homework: Worksheet
Adjustments for next time: 43
Course III – Math B Warm-Up
For 1 – 3 Use 4x =
12 x ! 9 x
1. The roots of this quadratic equation are: a. b. c. d.
Imaginary Real, rational, unequal Real, rational, equal Real, irrational, unequal
2. The sum of the roots is 3. The product of the roots is
Answer key to warm-up
1. c 2. 3 3. 9/4 44
Solving Quadratic Inequalities Notes We are looking for the points (zeros) on the x-axis that used to be solutions, but with inequalities they are ‘critical values’ One side of the critical value is a solution when we substitute the value for x or (t) the inequality is true, on one side of the critical value and false on the other. Ex) x2 – 2x – 3 < 0 Note: When we have an inequality with an exponent greater than one, we can solve it like an equation. 1) factor 2) quadratic formula if needed 3) calculator x2 – 2x – 3 < 0
Factor
x2 – 2x – 3 =0
Change < to = to find critical values, set = 0 & solve
(x – 3) ( x+1) = 0 x = 3 x = -1
-1
0
3
Now graph : Ask yourself open circle or closed Which way to shade? Do a test point. Substitute a value that is between the two critical values. (0)2 – 2(0) – 3 < 0 Is this true? -3 < 0 Yes so shade in to include 0 Now write it in the correct notation. {x|-1 0
{x|x2)} {x| -7 ≤ x ≤ 0} {x|x3} 45
16. x2 +8x + 7 ≥ 0
{x | x≤ -7 or x ≥ -1}
18. x2 +2x < 15
{x| -5 < x < 3}
20. 4x2 – 9 ≥ 0
{x |x ≤-3/2 or x ≥ 3/2}
Hand out hw sheet
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Course 3 Worksheet - Quadratic Inequalities Graph the solution set of: 1. x 2 - 4 < 0
2. x 2 - 2 5 > 0
3. x2 - 4x ≥ 0
4. x2 - 7x + 10 < 0
5. x2 - 5x - 24 ≤ 0
6. x2 > 8x + 20
7. x2 + 27 < 12x
8. 2x2 - 11x + 5 ≥ 0
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Answer key to hw. 1.
2.
-2 0, is determined by the equation h(t) = -I6t2 + 64t + 4. For which interval of time is the height of the ball greater than or equal to 52 feet? 1≤t≤3
Ask students if they have any questions with the test prep. Tell them to study and utilize the calculator.
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