MATHEMATICS 20-2 Quadratic Functions and Equations High School collaborative venture with Harry Ainlay, McNally, M. E. LaZerte, Ross Sheppard, Scona, and W.P. Wagner Harry Ainlay: Colin Veldkamp Harry Ainlay: Debby Sumantry Harry Ainlay: Mathias Stewart Harry Ainlay: Meriel Hughes McNally: Enchantra Gramlich M. E. LaZerte: Monique Merchant Ross Sheppard: Jeremy Klassen Ross Sheppard: Tim Gartke Scona: Joe Johnston W. P. Wagner: Kiki Brisebois Facilitator: John Scammell (Consulting Services) Editor: Jim Reed (Contracted) 2010 – 2011 TABLE OF CONTENTS STAGE 1 DESIRED RESULTS PAGE Big Idea 4 Enduring Understandings 4 Essential Questions 4 Knowledge 5 Skills 6 STAGE 2 ASSESSMENT EVIDENCE Transfer Tasks (on a separate page which can be photocopied & handed out to students) Bridge Design for the Masses Teacher Notes for Transfer Task Transfer Task Rubric Notes and Cautions Possible Solution Bridge Design for the Masses Transfer Task Rubric Possible Solution 7 8 15 17 18 28 30 31 STAGE 3 LEARNING PLANS Lesson #1 Getting to Know You (Characteristics Graphically) 36 Lesson #2 Split Personality (Characteristics Algebraically) 41 Lesson #3 Lesson 3: Solve by Factoring (Solve Equations) 46 Appendix – Worksheets/Keys Mathematics 20-2 52 Inductive and Deductive Reasoning Page 3 of 96 Mathematics 20-2 Quadratic Functions and Equations STAGE 1 Desired Results Big Idea: Important real world phenomena can be modeled by quadratic equations and functions. Understanding the properties of quadratic functions and equations enhances comprehension of these phenomena. There is an intricate connection among algebraic functions, the real world and graphs. Implementation note: Post the BIG IDEA in a prominent place in your classroom and refer to it often. Enduring Understandings: Students will understand … A quadratic function has a parabolic shape. Quadratic equations can be solved in a variety of ways. Quadratic functions and equations can model real world phenomena. The key features of a quadratic function have contextual significance. There are relationships among the roots of an equation, the zeros of the corresponding function and the x-intercepts of the graph of the function. Essential Questions: What property of a quadratic function makes it symmetrical? Why does it rise and fall or fall and rise? To what extent can a quadratic function describe increasing profit in business? What factors affect the path of a projectile? What causes natural phenomena to be quadratic? Do we invent math to describe our world or does math describe what is inherently there? Mathematics 20-2 Inductive and Deductive Reasoning Page 4 of 96 Knowledge: Enduring Understanding Specific Outcomes Description of Knowledge Students will know … Students will understand… A quadratic function has a parabolic shape. Quadratic equations can be solved in a variety of ways. Quadratic functions and equations can model real world phenomena. The key features of a quadratic function, expressed in a variety of ways, have contextual significance. There are relationships among the roots of an equation, the zeros of the corresponding function and the xintercepts of the graph of the function. 8888 I*RF = *RF1 *RF2 the general shape of a parabola the vertex, intercepts, domain & range and axis of symmetry the maximum and minimum values how to sketch/plot graphs how to identify the vertex of a quadratic from the standard form or graph identify the opening direction Students will know … when to find the x-intercept or vertex x-intercepts are zeros and roots what solve means the difference between functions and equations how to use the quadratic formula when to solve an equation Relations and Functions Mathematics 20-2 Inductive and Deductive Reasoning Page 5 of 96 Skills: Enduring Understanding Specific Outcomes Description of Skills Students will be able to… Students will understand… A quadratic function has a parabolic shape. Quadratic equations can be solved in a variety of ways. Quadratic functions and equations can model real world phenomena. The key features of a quadratic function, expressed in a variety of ways, have contextual significance. There are relationships among the roots of an equation, the zeros of the corresponding function and the xintercepts of the graph of the function. *RF1 convert an equation from standard form to vertex form determine the vertex: o from a graph o from an equation in standard form o using technology determine intercepts: o from a graph o from an equation in standard form o using technology determine the domain & range from a graph sketch the graph of a quadratic function with or without technology determine the equation of the axis of symmetry Students will be able to… *RF2 solve a quadratic equation by factoring and/or the quadratic formula write the function in factored form given the zeros of a quadratic determine the number of x-intercepts of a quadratic function solve contextual problems *RF = Relations and Functions Implementation note: Teachers need to continually ask themselves, if their students are acquiring the knowledge and skills needed for the unit. Mathematics 20-2 Inductive and Deductive Reasoning Page 6 of 96 STAGE 2 1 Assessment Evidence Desired Results Desired Results Teacher Notes There are 2 transfer tasks to evaluate student understanding of the concepts relating to quadratic functions and equations. A photocopy-ready version is included for both tasks. Implementation note: Students must be given the transfer task & rubric at the beginning of the unit. They need to know how they will be assessed and what they are working toward. When work is judged to be limited or insufficient, the teacher makes decisions about appropriate intervention to help the student improve. Each student will: Explain the concepts relating to quadratic functions and equations. Glossary factored form – A quadratic function written in the form y = a(x - r)(x - s) , where a, r, and s are real numbers and a ≠ 0 parabola – A U-shaped curve obtained by graphing a quadratic function standard form – A quadratic function written in the form y = ax2 + bx + c, where a, b, and c are real numbers and a ≠ 0 vertex form – A quadratic function written in the form y = a (x – p)2 + q, where a, p, and q are real numbers and a ≠ 0 vertex of a parabola – The point of intersection of a parabola and its axis of symmetry quadratic formula – The formula for determining the roots of a quadratic equation from its coefficients Mathematics 20-2 Inductive and Deductive Reasoning Page 7 of 96 Bridge Design for the Masses - Student Assessment Task Role: You are working with a team of bridge designers and you have been asked to create a bridge to cross the North Saskatchewan. Audience: City Council is eagerly waiting to see what you come up with. Format: Create a short report to summarize your findings and those of your colleague. Topic: Quadratic Functions and Equations Scenario A You have been asked to design a bridge to span the North Saskatchewan, and you are leaning towards a parabolic shape, but you have some research to do first. The bridge must span 120 m to get from one side of the river to the other, in the spot requested by City Council. Your first task is to determine the equation of your quadratic in the form , where r and s are the x-intercepts of the graph. You will need to identify some properties of your model. Make sure that in your report you: Identify the axis of symmetry. Find the y-coordinate of the vertex and determine whether it is a maximum or a minimum. Identify the domain and range Include a sketch of your model on the grid provided Move the axes to create at least two different sets of r and s values. Determine the new equation and verify that the maximum or minimum value is the same as that in the first equation. Comment on the feasibility of your model and what, if anything could be changed to improve it Bridge Design for the Masses (continued) Scenario B A colleague is also working on a bridge model. His quadratic model is y = a(x 2 - 25x -12) . He is having difficulty with this model, but he believes the problem can be fixed by altering the value of a. Your colleague has asked for your help. Choose two values for a in the interval –5 to –1. For each of these new equations find the x-intercepts of the graph. In one case use the calculator to find these values, and in the other use the quadratic formula. Round your answers to the nearest hundredth in both cases. What do you notice about your x-intercepts in each case, and what does this mean? For both of these models find the maximum height of the structure. Comment on the impact of a in the quadratic function. Your colleague also needs to determine an equation that will restrict the maximum height range to 25 m – 30 m. Generate a quadratic equation that meets this condition, while maintaining the same x-intercepts. Bridge Design for the Masses (continued) Scenario C Your bridge inspector colleague received plans for the construction of a walkway bridge to be known as the PiederManz Bridge, and has given you a copy of his notes. There are two parts to the design; a bridge support which has a parabolic shape, and a linear walkway intersecting the support. He has concerns that the walkway will be unsafe. The following artist’s rendering shows the walkway bridge over a small market between a river and road. B A Source: http://www.newcastle-guide.co.uk/images/stories/tyne-bridges042.JPG Bridge Inspector Notes: The maximum height of the bridge support is to be 55 m above the ground, and the distance between the supports on the ground is to be about 160 m. The equation of the support is given by h(x) = –111280(x – 80)2 + 55, where h is the height above ground, in meters, and x is the distance, in meters, from the bottom of the left end of the support. The walkway intersects the bridge support at a height of 32 m above the ground (point A at the left), and intersects it at a height of 37 m above ground at the right (point B). I’m not sure the distance between A and B is short enough! I’m also not sure how steep this walkway is, and I’m fearful that some elderly folks may slip and fall in the winter. You know that the length of the walkway between the supports needs to be less than 100 m, and that the grade of the walkway needs to be less than 5%. Based on your colleague’s notes, comment on the safety of the bridge design. Bridge Design for the Masses (continued) Scenario A: Show your work here. y = – (x – r)(x – s) Bridge Design for the Masses (continued) A B source: http://t3.gstatic.com/images?q=tbn:ANd9GcQ0OBEsEh86rnP4b2ojvnzEHPVz7hQegYTNAtN3A4HpGt7ug77Lg Discuss your model’s feasibility and your suggestions here: Bridge Design for the Masses (continued) Scenario B: Show your work here. y = a(x2 – 25x – 12) Comment on the impact of a. State the equation you found: Bridge Design for the Masses (continued) Scenario C: Show your work here. h(x) = –111280(x – 80)2 + 55 Comment on your colleague’s design. Bridge Design for the Masses (continued) Glossary factored form – A quadratic function written in the form y = – (x – r)(x – s), where a, r, and s are real numbers and a ≠ 0 parabola – A U-shaped curve obtained by graphing a quadratic function standard form – A quadratic function written in the form y = ax2 + bx + c, where a, b, and c are real numbers and a ≠ 0 vertex form – A quadratic function written in the form y = a (x – p)2 + q, where a, p, and q are real numbers and a ≠ 0 vertex of a parabola – The point of intersection of a parabola and its axis of symmetry quadratic formula – The formula for determining the roots of a quadratic equation from its coefficients Assessment Bridge Design for the Masses Rubric Component Description of Requirements - Scenario A - Appropriate factored form of equation - Identifies axis of symmetry, vertex, domain and range Identifies a valid second equation with verification Mathematical Content - Scenario B - Correct x-intercepts found in prescribed manner - Appropriate equation (a-value) stated - Scenario C - Determines proper length and grade of walkway Presentation - Report is easy to read of Data - Math work is complete and easy to follow - Graph is complete and accurate (scale, labels, neatly drawn) Explanations - Comment/recommendations on the feasibility of of Choices the model of the equation in Scenario A. - Conclusions about x-intercepts and impact of a in Scenario B are appropriate. - Conclusions about walkway are appropriate in Scenario C Assessment IN 1 2 3 4 IN 1 2 3 4 IN 1 2 3 4 IN 1 2 3 4 IN 1 2 3 4 Bridge Design for the Masses (continued) Level Criteria Math Content Scenario A Excellent 4 All required elements are present and correct Math Content Scenario B All required elements are present and correct Math Content Scenario C All required elements are present and correct Presents Data Presentation of data is clear, precise and accurate Explains Choices Provides insightful explanations Proficient 3 All required elements are present but may contain minor errors Adequate 2 Some required elements are missing, or contain major errors All required Some elements are required present but elements are may contain missing, or minor errors contain major errors All required Some elements are required present but elements are may contain missing, or minor errors contain major errors Presentation Presentation of data is of data is complete simplistic and and unambiguo plausible us Provides Provides logical explanations explanations that are complete but vague Limited 1 Most required elements are missing or incorrect Insufficient Blank No score is awarded as there is no evidence given Most required elements are missing or incorrect No score is awarded as there is no evidence given Most required elements are missing or incorrect No score is awarded as there is no evidence given Presentation of data is vague and inaccurate Presentation of data is incomprehe nsible Provides explanations that are incomplete or confusing. No explanation is provided When work is judged to be limited or insufficient, the teacher makes decisions about appropriate intervention to help the student improve. Implementation note: Teachers need to consider what performances and products will reveal evidence of understanding? What other evidence will be collected to reflect the desired results? Mathematics 20-2 Inductive and Deductive Reasoning Page 16 of 96 Bridge Design for the Masses Notes and Cautions The thought in designing this transfer task was that students would complete two of the three scenarios. In Scenario A students may need some direction to adjust the (vertical) scale of the graph to accommodate the height of the vertex. In Scenario B encourage students to use logic and verification, and to round their avalues to the nearest hundredth. In Scenario C this section can be assigned as is, or can be adjusted. One suggestion is to add a recommendation to the colleague (so that the grade problem is fixed). If a student attempts to find the x-value of the walkway algebraically, they may need some guidance as each y-value produces an extraneous root. First Possible Solution to Bridge Design for the Masses Scenario A Mathematics 20-2 Quadratic Functions and Equations Page 18 of 96 Mathematics 20-2 Quadratic Functions and Equations Page 19 of 96 Scenario B Mathematics 20-2 Quadratic Functions and Equations Page 20 of 96 Scenario C Mathematics 20-2 Quadratic Functions and Equations Page 21 of 96 Mathematics 20-2 Quadratic Functions and Equations Page 22 of 96 Second Possible Solution to Bridge Design for the Masses Scenario A Mathematics 20-2 Quadratic Functions and Equations Page 23 of 96 Mathematics 20-2 Quadratic Functions and Equations Page 24 of 96 Scenario B Mathematics 20-2 Quadratic Functions and Equations Page 25 of 96 Scenario C Mathematics 20-2 Quadratic Functions and Equations Page 26 of 96 Mathematics 20-2 Quadratic Functions and Equations Page 27 of 96 Public Awareness Campaign - Student Assessment Task Situation There has been an anti quadratics movement afoot in the school system organized by a strongly opinionated parent group. The parent group wants to remove quadratic equations and functions from the Alberta Mathematics Curriculum for the following reasons: There are limited applications of quadratic functions. Quadratic equations are too difficult to solve. The information gathered from a quadratic function is not relevant to the real world. People function in the real world without graphs of quadratics. Goal Create a public awareness campaign to stress the importance of quadratics in mathematics and real world applications. Mathematics 20-2 Quadratic Functions and Equations Page 28 of 96 Public Awareness Campaign (continued) Role: You are to choose one of the following methods to support your public relations campaign. Oral Projects Products Multimedia Newscast - Presentation and Planning Making A Brochure PowerPoint Presentation Making A Poster Video Presentation Puppet Show Story Telling Newspaper (ad, article or editorial) Video - Talk Show Audience You are to present to the mock parent group and convince them that quadratic functions and equations are a valuable asset to the Alberta Mathematics Curriculum. Product Your product should include: Four examples of parabolas in the real world. Include visuals. For one of your examples: Identify the vertex and its significance. Identify the y-intercept and its significance. Identify the number of x-intercepts and their significance. Determine the domain and range within the context of your example. Two quadratic equations in standard form: Calculate the x-intercepts using a minimum of two methods. Clearly show (or explain) all steps. Generate graphs of two quadratic functions, one in standard form and one in vertex form, using two of the following methods. table of values graphing calculator plot x-intercepts, y-intercept and vertex Public Awareness Campaign Rubric Level Excellent 4 Proficient 3 Adequate 2 Limited* 1 Criteria Performs Performs precise and Performs focused and Performs Performs Calculations explicit calculations. accurate calculations. appropriate and superficial generally accurate and irrelevant States two Correctly identified Correctly identified quadratic calculations. calculations. four intercepts two or three equations in Correctly Some intercepts standard form: identified one correct Calculates the intercept algebra but x-intercepts no using a correctly minimum of identified two methods. intercepts Clearly explains all steps. Indentifies Identifies the vertex Was able to correctly Missed two Missed and explains and its significance identify three of the important key three significance including identifying key points points important of key points as a maximum or key points of quadratics. minimum Identifies the yintercept and its significance Identifies the number of x-intercepts and their significance Determines the domain and range within the context of the example Communicate Develops a Develops a Develops a Develops an s findings, compelling and convincing and predictable unclear include precise presentation logical presentation presentation that presentation visuals and that fully considers that mostly considers partially considers with little graphs consideration the purpose and the purpose and the purpose and audience; uses audience; uses audience; uses of purpose and appropriate appropriate some appropriate audience; mathematical mathematical mathematical uses inappropriate vocabulary, notation vocabulary, notation vocabulary, and symbolism and symbolism notation and mathematical symbolism vocabulary, notation and symbolism Real life or Includes four real life Includes three real life Includes real life Includes real real work applications clearly applications clearly applications not life application linked to the real clearly linked to the applications linked to the real are included world or four with limited world. real world applications not applications to clearly linked to the the real world real world Mathematics 20-2 Quadratic Functions and Equations Insufficient/ Blank* No score is awarded because there is no evidence of student performance No data is presented No findings are communicated No real life examples are included Page 30 of 96 Possible Solutions to Public Awareness Campaign Screenshot of Brochure Exemplar SmartBoard Exemplar (MS Word) SmartBoard Exemplar (PDF) files were added to the EPSB Understanding by Design share site Screenshot of SmartBoard Exemplar Public Awareness Campaign Exemplar (Notebook) file was added to the EPSB Understanding by Design share site Mathematics 20-2 Quadratic Functions and Equations Page 31 of 96 Screenshot of Video Exemplar (Presentation of SmartBoard file) Video Exemplar (small file): http://dl.dropbox.com/u/6062352/Quadratics Transfer Task Exemplar. Smaller.mp4 (large file): http://dl.dropbox.com/u/6062352/Quadratics Transfer Task Exemplar.m4v Public Awareness Video Script file was added to the EPSB Understanding by Design share site Mathematics 20-2 Quadratic Functions and Equations Page 32 of 96 STAGE 3 Learning Plans Lesson 1 Characteristics: Graphically STAGE 1 BIG IDEA: Important real world phenomena can be modeled by quadratic equations and functions. Understanding the properties of quadratic functions and equations enhances comprehension of these phenomena. There is an intricate connection among algebraic functions, the real world and graphs. ENDURING UNDERSTANDINGS: ESSENTIAL QUESTIONS: Students will understand … A quadratic function has a parabolic shape. Quadratic functions and equations can model real world phenomena. The key features of a quadratic function, expressed in a variety of ways, have contextual significance. There are relationships among the roots of an equation, the zeros of the corresponding function and the x-intercepts of the graph of the function. What property of a quadratic function makes it symmetrical? Why does it rise and fall or fall and rise? What factors affect the path of a projectile? Do we invent math to describe our world or does math describe what is inherently there? KNOWLEDGE: SKILLS: Students will know … Students will be able to … the general shape of a parabola the vertex, intercepts, domain & range and axis of symmetry the maximum and minimum values how to sketch/plot graphs how to identify the vertex of a quadratic from the standard form or graph identify the opening direction when to find the x-intercept or vertex x-intercepts are zeros and roots the difference between functions and equations determine the vertex: o from a graph o from an equation in standard form o using technology determine intercepts: o from a graph. o from an equation in standard form o using technology determine the domain & range from a graph sketch the graph of a quadratic function with or without technology Implementation note: Each lesson is a conceptual unit and is not intended to be taught on a one lesson per block basis. Each represents a concept to be covered and can take anywhere from part of a class to several classes to complete. Mathematics 20-2 Quadratic Functions and Equations Page 33 of 96 Lesson Summary Introduce quadratic functions. Given a graph of a quadratic function, find the y-intercept, vertex, x-intercepts, domain and range. Given a quadratic function, make a table of values and graph. Look at symmetry of a parabola and introduce axis of symmetry. Given a quadratic function, use a calculator to determine the vertex, x-intercepts, yintercept, axis of symmetry, and domain and range. Lesson Plan Hook Show the waterslide video. Explain this is a real life example of a nonlinear relationship. This unit is focusing on a nonlinear function called a quadratic. Waterslide video Source: http://www.youtube.com/watch?v=Fyo-nhoNW54 Mathematics 20-2 Quadratic Functions and Equations Page 34 of 96 Lesson Goal Students will be able to identify the vertex, axis of symmetry, intercepts, domain and range of a quadratic function given a graph or a function (standard and vertex form). Activate Prior Knowledge Display a graph of a quadratic function that opens down (no scale on grid) and ask students to come up with a scenario that could be represented by the graph. Introduce the term parabola and emphasize that this shape is parabolic. Lesson Part 1 Give a picture of Angry Bird. Source: http://media.photobucket.com/image/angry%20birds%20projectile/leonography/News/angrybirdT02.jpg What do you want to know about this bird? Potential questions: How high did the bird go? How high was it when it was launched? Where will it land? How long was it in the air? Mathematics 20-2 Quadratic Functions and Equations Page 35 of 96 Give a picture of Angry Bird with a grid superimposed on it and a graph of the path (integral key points). Can we answer these questions using this graph? or Source: John Scammell’s iPad What are the key points on this curve? Introduce the term vertex and discuss vertex, domain, range and intercepts. Mathematics 20-2 Quadratic Functions and Equations Page 36 of 96 Part 2 Show second video clip with different contexts for parabolas. source: http://qwickstep.com/search/skateboarding-half-pipe.html Show the picture and discuss the structure of the half pipe and/or the path of the skateboarder from one side to the other. The function that approaches this situation is h = 4(t – 1.5)2 + 3 and is shown in the graph below. 1. 2. 3. 4. 5. 6. What do h and t represent in the function? How does that relate to the graph? How high is he in the picture? What’s the lowest height on the graph? How long does it take him to reach the other side? What are the domain and range for this function? DI Suggestion Discuss why there are no x-intercepts for this situation. Discuss why we have to say that a halfpipe approaches a quadratic function. Mathematics 20-2 Quadratic Functions and Equations Page 37 of 96 Give students a function in standard form. Example: y = – 2(x – 5)2 + 50 Provide x-values for the table of values that will provide students with symmetry cues. Have students determine the y-values, then sketch the graph using the table of values. Talk about the symmetry shown in the table of values. What are the key points for this curve? Introduce the axis of symmetry. Give students a graph (on labelled grid) that opens up with no x-intercepts. Ask them to determine the key points (x-intercepts, y-intercept, vertex). We’ve looked at a graph with 2 xintercepts and one with no x-intercepts, are there any other possibilities? Draw a sketch. DI Suggestion Consider a discussion about graphs and the quadrants containing data points. Part 3 Show a video clip of a soccer goal. A shortened version of this video was added to the same folder as this file. Before showing the function consider discussing the characteristics of the graph of the function. If the ball is kicked at (0, 0) and lands at (4, 0) answer the following What is the axis of symmetry? Where is the vertex? Is the y-coordinate of the vertex a maximum or minimum? (RF 1.3) L1 Soccer Goal file was added to the EPSB Understanding by Design share site original source: http://www.youtube.com/watch?v=X72R9yu_4hU&feature=fvw The path of the ball is represented by the function y = –2x2 + 8x, where y represents the height of the ball off the ground in metres, and x represents time in seconds. Instruct how to find the key points using the calculator. Look at questions like how high is the ball at 1.6 s and/or at what time does the ball reach a height of 5.5 m? Discuss applicable domain and range. DI Suggestion Consider making a mini book with calculator functions. Mathematics 20-2 Quadratic Functions and Equations Page 38 of 96 Going Beyond Resources Math 20-2 (Nelson: sec 6.1, 6.2, 6.4, 6.5 page(s) 322-336, 354-382) Watch a video of different parabolic scenarios. Source: http://www.learnalberta.ca/content/mejhm/html/video_interactives/polynomials/movie.html Supporting Assessment Mathematics 20-2 Quadratic Functions and Equations Page 39 of 96 Glossary axis of symmetry - A line that separates a figure into two equal parts domain - All possible independent values for a relation maximum value - The greatest value of a dependent variable of a relation minimum value - The least value of a dependent variable of a relation parabola – A U-shaped curve obtained by graphing a quadratic function quadratic equation – An equation of the form ax2 + b x + c = 0, where a, b, and c are real numbers and a ≠ 0 quadratic function – A function that may be written in the form y = ax2 + b x + c, where a, b, and c are real numbers and a ≠ 0 quadratic relation – A relation that can be written in the standard form ax2 + b x + c = 0, where a, b, and c are real numbers and a ≠ 0 [Math 20-2 (Nelson, page 517)] range - All possible dependent values for a relation root – A solution of an equation vertex of a parabola – The point of intersection of a parabola and its axis of symmetry x-intercept - The horizontal value of the point where the curve intersects the horizontal axis y-intercept - The vertical value of the point where the curve intersects the vertical axis. zero – The value of the independent variable of a function for which the function equals zero Other Mathematics 20-2 Quadratic Functions and Equations Page 40 of 96 Lesson 2 Characteristics: Algebraically STAGE 1 BIG IDEA: Important real world phenomena can be modeled by quadratic equations and functions. Understanding the properties of quadratic functions and equations enhances comprehension of these phenomena. There is an intricate connection among algebraic functions, the real world and graphs. ENDURING UNDERSTANDINGS: ESSENTIAL QUESTIONS: Students will understand … A quadratic function has a parabolic shape. Quadratic functions and equations can model real world phenomena. The key features of a quadratic function, expressed in a variety of ways, have contextual significance. There are relationships among the roots of an equation, the zeros of the corresponding function and the x-intercepts of the graph of the function. What property of a quadratic function makes it symmetrical? Why does it rise and fall or fall and rise? What factors affect the path of a projectile? What causes natural phenomena to be quadratic? Do we invent math to describe our world or does math describe what is inherently there? KNOWLEDGE: SKILLS: Students will know … Students will be able to … the general shape of a parabola the vertex, intercepts, domain & range and axis of symmetry the maximum and minimum values how to sketch/plot graphs how to identify the vertex of a quadratic from the standard form or graph identify the opening direction when to find the x-intercept or vertex x-intercepts are zeros and roots when to solve an equation Mathematics 20-2 determine the vertex: o from a graph o from an equation in standard form o using technology determine intercepts: o from a graph. o from an equation in standard form o using technology determine the domain & range from a graph sketch the graph of a quadratic function with or without technology determine the equation of the axis of symmetry. solve a quadratic equation by factoring and/or the quadratic formula write the function in factored form given the zeros of a quadratic determine the number of x-intercepts of a quadratic function solve contextual problems Quadratic Functions and Equations Page 41 of 96 Lesson Summary In this lesson students will explore the effects of the parameters of quadratic functions in vertex form, standard form and factored form. Lesson Plan Lesson Goal Students will see how the different forms of equations relate to the characteristics of quadratic functions. Students will discover the effects each parameter (for each form) has on the graph. Activate Prior Knowledge What do you see activity Using the image of a quadratic function below, ask the students “What do you see?” A Think-Pair-Share is a possible way to promote student discussion about the graph. Student discussion will hopefully lead to a discussion about the characteristics of a quadratic function (vertex, intercepts, axis of symmetry, domain and range.) Mathematics 20-2 Quadratic Functions and Equations Page 42 of 96 Lesson Students will investigate the properties for vertex, standard, and factored form of the quadratic function Goal is to see that: Vertex form is useful for determining the vertex, direction of opening, and shape of the graph. Standard form is useful for determining the y-intercept, direction of opening, and shape of the graph. Factored form is useful for determining the x-intercepts, direction of opening, and shape of the graph. At the end of the each section you may use an applet to visually reinforce the students learning. 1. Vertex Form: y = a(x – p) 2 + q source: http://members.shaw.ca/jreed/math20-2/ubd/quadratic.htm L2 Investigate Vertex Form and Key copy was added to Appendix file was added to the EPSB Understanding by Design share site 2. Jig saw vertex, standard, and factored forms activity: Students will practice graphing quadratic functions from the different forms. The goal of the Jig Saw Activity is for students: Mathematics 20-2 Quadratic Functions and Equations Page 43 of 96 to see that the different forms of a quadratic function can all result in the same graph to understand the advantages and disadvantages of each form L2 Jig Saw Equation Forms and Key copy was added to Appendix file was added to the EPSB Understanding by Design share site 3. Jig saw applications activity: Students will practice solving different types of application questions involving quadratics. L2 Jig Saw Applications and Key copy was added to Appendix file was were added to the EPSB Understanding by Design share site Instructions Arrange students in groups of 4. Each student will receive a different question (Circle, Triangle, Square, Star) and individually work on their problem. Similar shapes will meet, compare their work, and become experts on their problem. Bring students back to their original groups and each student will present their problem and solution to the entire group. 4. Graphs, equations, and characteristics matching activity Students complete the activity to show their understanding of the characteristics of quadratic functions and the different forms of the equations of quadratic functions L2 Matching Activity with Key copy was added to Appendix file was added to the EPSB Understanding by Design share site 5. Finding equations of quadratic functions Now that students are familiar with the different forms of quadratic functions they can practice finding the equations. Consider using the examples from the first lesson to practice finding equations. Going Beyond Resources Math 20-2 (Nelson: sec 6.1 – 6.5, page(s) 322-382) Mathematics 20-2 Quadratic Functions and Equations Page 44 of 96 Supporting Assessment Glossary axis of symmetry - A line that separates a figure into two equal parts domain - All possible independent values for a relation factored form – A quadratic function written in the form y = a(x – r) (x – s), where a, r, and s are real numbers and a ≠ 0 maximum value - The greatest value of a dependent variable of a relation minimum value - The least value of a dependent variable of a relation parabola – A U-shaped curve obtained by graphing a quadratic function quadratic formula – The formula for determining the roots of a quadratic equation from its coefficients range - All possible dependent values for a relation standard form – A quadratic function written in the form y = ax2 + bx + c, where a, b, and c are real numbers and a ≠ 0 vertex form – A quadratic function written in the form y = a (x - p)2 + q, where a, p, and q are real numbers and a ≠ 0 vertex of a parabola – The point of intersection of a parabola and its axis of symmetry x-intercept - The horizontal value of the point where the curve intersects the horizontal axis y-intercept - The vertical value of the point where the curve intersects the vertical axis. zero – The value of the independent variable of a function for which the function equals zero Other Mathematics 20-2 Quadratic Functions and Equations Page 45 of 96 Lesson 3 Lesson 3: Solve by Factoring (Solve Equations) STAGE 1 BIG IDEA: Important real world phenomena can be modeled by quadratic equations and functions. Understanding the properties of quadratic functions and equations enhances comprehension of these phenomena. There is an intricate connection among algebraic functions, the real world and graphs. ENDURING UNDERSTANDINGS: ESSENTIAL QUESTIONS: Students will understand … A quadratic function has a parabolic shape. Quadratic equations can be solved in a variety of ways. Quadratic functions and equations can model real world phenomena. The key features of a quadratic function, expressed in a variety of ways, have contextual significance. There are relationships among the roots of an equation, the zeros of the corresponding function and the x-intercepts of the graph of the function. What property of a quadratic function makes it symmetrical? Why does it rise and fall or fall and rise? To what extent can a quadratic function describe increasing profit in business? What factors affect the path of a projectile? What causes natural phenomena to be quadratic? Do we invent math to describe our world or does math describe what is inherently there? KNOWLEDGE: SKILLS: Students will know … Students will be able to … axis of symmetry how to sketch/plot graphs identify the opening direction when to find the x-intercept or vertex x-intercepts are zeros and roots what solve means the quadratic formula when to solve an equation Mathematics 20-2 determine the vertex: o from a graph o from an equation in standard form o using technology determine intercepts: o from a graph. o from an equation in standard form o using technology sketch the graph of a quadratic function with or without technology solve a quadratic equation by factoring and/or the quadratic formula write the function in factored form given the zeros of a quadratic determine the number of x-intercepts of a quadratic function solve contextual problems Quadratic Functions and Equations Page 46 of 96 Lesson Summary Zeros are the x-intercepts of the graph of the corresponding quadratic function and the roots of the corresponding quadratic equation. Methods for finding the roots of (solving) a quadratic equation include: graphing factoring quadratic formula rectangles and algebra tiles Checking/verifying the root(s) require(s) substitution or the zero feature on the graphing calculator. Lesson Plan Hook (x - 3)(x - 5) = 0 What do we call this form of a quadratic equation? Lesson Goal Students should be able to determine, by factoring, the roots of a quadratic equation and verify by substitution. Activate Prior Knowledge Review rectangles and algebra tiles. The following applet shows 3 polynomials with a leading coefficient of 1. Two buttons give opportunity to explore factoring with and without tiles for leading coefficients of 1 (Natural/Integers). The last button provides opportunity to explore expressions where the leading coefficient is not 1. source: http://staff.argyll.epsb.ca/jreed/math9/strand2/factor1.htm It would be useful for students to be able to switch between polynomial, rectangular representation, grid and factors. An assignment with 4 columns with one example in each column should help students show multiple representations of the same expression. Mathematics 20-2 Quadratic Functions and Equations Page 47 of 96 L3 Rectangles and Algebra Tiles Completion Assignment copy was added to Appendix file was added to the EPSB Understanding by Design share site Factoring review examples: Factoring Trinomials Example: 6x2 + 14x - 12 2(3x2 + 7x – 6) GCF First! Factor Pictorially Factor Symbolically Difference of Squares Example: 27x2 - 75 2 GCF First! 2(9x – 25) Factor Pictorially Factor Symbolically L3 Factoring Review Examples copy was added to Appendix file was added to the EPSB Understanding by Design share site Mathematics 20-2 Quadratic Functions and Equations Page 48 of 96 Lesson Discuss with students the possible values for a & b in ab = 0 solutions for 2b = 0 and a(5) = 0 solutions for 2(x + 3) = 0 and (x + 7)(5) = 0 solutions for (x - 3)(x - 5) = 0 solutions for x(x - 5) = 0 Emphasize that roots and solutions are equivalent terms. Students should enter the function y = (x - 3)(x - 5) into their graphing calculators and determine the zeros. Remind students that zeros of a function are the x-intercepts of the graph of the function. To help students link the terms solutions, roots, zeros and x-intercepts have them look up the textbook (alternatively, display on screen) definition for zeros: “In a function, the value of the variable that makes the value of the function equal to zero.” (Nelson) Ask “How do y = (x - 3)(x - 5) and (x - 3)(x - 5) = 0 relate to each other?” Differentiate between the ordered pairs of zeros and x-intercepts with the x-values of the solutions and roots. Explain that solving means making y = 0 or making the function equal to zero Emphasize that in order to solve an equation, it must be equal to 0. Quadratic Formula It may useful for students to see factoring visually and algebraically. The following applet shows the same quadratic solved by quadratic formula, graphing and factoring. source: http://staff.argyll.epsb.ca/jreed/math9/strand2/factor2.htm L3 Solving Using the Quadratic Formula copy was added to Appendix file was added to the EPSB Understanding by Design share site Mathematics 20-2 Quadratic Functions and Equations Page 49 of 96 Show students how to solve these examples: x2 - 2x - 120 = 0 and -3.4x2 + 10.2x + 61.2. Discuss how students can check their answers (graphing calculator, verifying algebraically by substitution, …). Split the students into groups of 4 to solve a package of equations. L3 Solving Equations Questions and Key copy was added to Appendix file was added to the EPSB Understanding by Design share site Going Beyond The text resource has a number of contextual problems. Resources Math 20-2 (Nelson: sec 6.3, page(s) 405-413) Math 20-2 (Nelson: sec 7.2, page(s) 337-349) Supporting Assessment Glossary axis of symmetry - A line that separates a figure into two equal parts domain - All possible independent values for a relation factored form – A quadratic function written in the form y = a(x - r)(x - s), where a, r, and s are real numbers and a ≠ 0 maximum value - The greatest value of a dependent variable of a relation minimum value - The least value of a dependent variable of a relation parabola – A U-shaped curve obtained by graphing a quadratic function Mathematics 20-2 Quadratic Functions and Equations Page 50 of 96 quadratic equation – An equation of the form ax2 + b x + c = 0, where a, b, and c are real numbers and a ≠ 0 quadratic formula – The formula for determining the roots of a quadratic equation from its coefficients range - All possible dependent values for a relation root – A solution of an equation standard form – A quadratic function written in the form y = ax2 + bx + c, where a, b, and c are real numbers and a ≠ 0 vertex form – A quadratic function written in the form y = a (x - p)2 + q, where a, p, and q are real numbers and a ≠ 0 vertex of a parabola – The point of intersection of a parabola and its axis of symmetry x-intercept - The horizontal value of the point where the curve intersects the horizontal axis y-intercept - The vertical value of the point where the curve intersects the vertical axis. zero – The value of the independent variable of a function for which the function equals zero Other Mathematics 20-2 Quadratic Functions and Equations Page 51 of 96 Appendix Copies of worksheets for Lessons 2 – 3 follow: Lesson 2 Investigate Vertex Form and Key Lesson 2 Jig Saw Applications and Key Lesson 2 Jig Saw Equation Forms and Key Lesson 2 Matching Activity with Key Lesson 3 Rectangles and Algebra Tiles Completion Assignment Lesson 3 Factoring Review Examples Lesson 3 Solving Using the Quadratic Formula Lesson 3 Solving Equations Questions and Key Mathematics 20-2 Quadratic Functions and Equations Page 52 of 96 M20-2 Lesson 2 Investigate Vertex Form Investigate 𝑦 = (𝑥 − ℎ)2 For the following equations 𝑦 = 𝑥 2 𝑦 = (𝑥 − 2)2 𝑦 = (𝑥 + 1)2 , 1. Complete the table of values. 2. Plot the points on the grid using different colors for each equation. 3. For each equation, complete the chart below the grid. 𝒚 = (𝒙 − 𝟐)𝟐 x y 0 1 2 3 4 𝒚 = 𝒙𝟐 x -2 -1 0 1 2 y 𝒚 = 𝒙𝟐 𝒚 = (𝒙 − 𝟐)𝟐 𝒚 = (𝒙 + 𝟏)𝟐 x y -3 -2 -1 0 1 𝒚 = (𝒙 + 𝟏)𝟐 Vertex Maximum or minimum value y-intercept x-intercept(s) Equation of the Axis of Symmetry Domain Range In General: The graph of y ( x h) 2 is the graph of y x 2 is moved along the x-axis… Left h units if: _____________. Right h units if: ___________. Investigate 𝑦 = 𝑥 2 + 𝑘 For the following equations 𝑦 = 𝑥 2 𝑦 = 𝑥2 + 3 𝑦 = 𝑥 2 − 2, 1. Complete the table of values. 2. Plot the points on the grid using different colors for each equation. 3. For each equation, complete the chart below the grid. Mathematics 20-2 Quadratic Functions and Equations Page 53 of 96 𝑦 = 𝑥2 + 3 x y 0 1 2 3 4 𝒚 = 𝒙𝟐 x -2 -1 0 1 2 y 𝑦 = 𝑥2 − 2 x y -3 -2 -1 0 1 𝑦 = 𝑥2 + 3 𝒚 = 𝒙𝟐 𝑦 = 𝑥2 − 2 Vertex Maximum or minimum value y-intercept x-intercept(s) Equation of the Axis of Symmetry Domain Range In General: The graph of 𝑦 = 𝑥 2 + 3 is the graph of y x 2 is moved along the y-axis… Up k units if: _____________. Down k units if: ___________. 2 Investigate 𝑦 = 𝑎𝑥 1 For the following equations 𝑦 = 𝑥 2 𝑦 = −𝑥 2 𝑦 = 2𝑥 2 𝑦 = 𝑥2, 2 1. Complete the table of values. 2. Plot the points on the grid using different colors for each equation. 3. For each equation, complete the chart below the grid. 𝑦 = −𝑥 2 𝒚 = 𝒙𝟐 x -2 -1 0 y Mathematics 20-2 x -2 -1 0 𝑦 = 2𝑥 2 y x -2 -1 0 𝑦= y Quadratic Functions and Equations x -2 -1 0 1 2 𝑥 2 y Page 54 of 96 1 2 1 2 𝒚 = 𝒙𝟐 1 2 𝑦 = −𝑥 2 1 2 𝑦 = 2𝑥 2 𝑦= 1 2 𝑥 2 Vertex Maximum or minimum value y-intercept x-intercept(s) Equation of the Axis of Symmetry Domain Range In General: The graph of y ax 2 is the graph of y x 2 is stretched. In General: If a 0 (negative), then the graph opens down. If 𝑎 > 0 (positive), then the graph opens up. A ball is thrown into the air from the balcony of an apartment building and falls to the ground. The height y (in meters) of the ball relative to the ground x seconds after being thrown is shown by the following quadratic function: Mathematics 20-2 Quadratic Functions and Equations Page 55 of 96 1. What is the approximate maximum height of the ball? 2. What is the y-intercept? 3. What is the height of the balcony? How does this height compare to the y-intercept? 4. How long does it take for the ball to hit the ground? 5. What is the x-intercept? How does this compare to the length of time it takes for the ball to hit the ground? 6. What is height of the ball after 5 seconds? It is going up or down? 7. The point at which the ball changes direction is called __________________? Mathematics 20-2 Quadratic Functions and Equations Page 56 of 96 M20-2 Lesson 2 Investigate Vertex Form Key Investigate 𝑦 = (𝑥 − ℎ)2 For the following equations 𝑦 = 𝑥 2 𝑦 = (𝑥 − 2)2 𝑦 = (𝑥 + 1)2 , 4. Complete the table of values. 5. Plot the points on the grid using different colors for each equation. 6. For each equation, complete the chart below the grid. 𝒚 = (𝒙 − 𝟐)𝟐 x y 0 1 2 3 4 𝒚 = 𝒙𝟐 x -2 -1 0 1 2 y 𝒚 = 𝒙𝟐 Vertex Maximum or minimum value y-intercept x-intercept(s) Equation of the Axis of Symmetry Domain Range (0, 0) min = 0 𝒚 = (𝒙 + 𝟏)𝟐 x y -3 4 -2 1 -1 0 0 1 1 4 𝒚 = (𝒙 − 𝟐)𝟐 (0, 2) min = 0 𝒚 = (𝒙 + 𝟏)𝟐 (0, -1) min = 0 0 0 x=0 4 0 x=2 1 0 x = -1 x∈R y≥0 x∈R y≥0 x∈R y≥0 In General: The graph of y ( x h) 2 is the graph of y x 2 is moved along the x-axis… Left h units if: _____ h < 0________. Right h units if: ______ h > 0_____. Investigate 𝑦 = 𝑥 2 + 𝑘 For the following equations 𝑦 = 𝑥 2 𝑦 = 𝑥2 + 3 𝑦 = 𝑥 2 − 2, 4. Complete the table of values. 5. Plot the points on the grid using different colors for each equation. Mathematics 20-2 Quadratic Functions and Equations Page 57 of 96 6. For each equation, complete the chart below the grid. 𝑦 = 𝑥2 + 3 x y 0 1 2 3 4 𝒚 = 𝒙𝟐 x -2 -1 0 1 2 y 𝒚 = 𝒙𝟐 Vertex Maximum or minimum value y-intercept x-intercept(s) Equation of the Axis of Symmetry Domain Range (0, 0) min = 0 𝑦 = 𝑥2 − 2 x y -3 5 -2 0 -1 -1 0 -2 1 -1 𝑦 = 𝑥2 + 3 (0, 2) min = 3 𝑦 = 𝑥2 − 2 (0, -1) min = -2 0 0 x=0 3 0 x=0 -2 0 x=0 x∈R y≥0 x∈R y≥3 x∈R y ≥ -2 In General: The graph of 𝑦 = 𝑥 2 + 3 is the graph of y x 2 is moved along the y-axis… Up k units if: ______ h > 0_______. Down k units if: ____ h < 0_______. Mathematics 20-2 Quadratic Functions and Equations Page 58 of 96 Investigate 𝑦 = 𝑎𝑥 2 1 For the following equations 𝑦 = 𝑥 2 𝑦 = −𝑥 2 𝑦 = 2𝑥 2 𝑦 = 2 𝑥2, 4. Complete the table of values. 5. Plot the points on the grid using different colors for each equation. 6. For each equation, complete the chart below the grid. 𝑦 = −𝑥 2 𝒚 = 𝒙𝟐 x -2 -1 0 1 2 y x -2 -1 0 1 2 𝒚 = 𝒙𝟐 𝑦 = 2𝑥 2 y x -2 -1 0 1 2 𝑦 = −𝑥 2 1 2 𝑥 2 𝑦= y 𝑦 = 2𝑥 2 Vertex (0, 0) (0, 0) (0, 0) Maximum or min = 0 min = 0 min = 0 minimum value y-intercept 0 0 0 x-intercept(s) 0 0 0 x=0 x=0 x=0 Equation of the Axis of Symmetry Domain x∈R x∈R x∈R Range y≥0 y≤0 y≥0 2 2 In General: The graph of y ax is the graph of y x is stretched. x -2 -1 0 1 2 𝑦= y 2 0.5 0 0.5 2 1 2 𝑥 2 (0, 0) min = 0 0 0 x=0 x∈R y≥0 In General: If a 0 (negative), then the graph opens down. If 𝑎 > 0 (positive), then the graph opens up. Mathematics 20-2 Quadratic Functions and Equations Page 59 of 96 A ball is thrown into the air from the balcony of an apartment building and falls to the ground. The height y (in meters) of the ball relative to the ground x seconds after being thrown is shown by the following quadratic function: 8. What is the approximate maximum height of the ball? 155 m 9. What is the y-intercept? y = 100 10. What is the height of the balcony? 100 m How does this height compare to the y-intercept? The height of the balcony is the y-intercept. 11. How long does it take for the ball to hit the ground? 20 s 12. What is the x-intercept? 20 How does this compare to the length of time it takes for the ball to hit the ground? The time it takes the ball to hit the ground is the x-intercept. 13. What is height of the ball after 5 seconds? 150 s It is going up or down? up 14. The point at which the ball changes direction is called ______the vertex____________? Mathematics 20-2 Quadratic Functions and Equations Page 60 of 96 M20-2 Lesson 2 Jig Saw Applications Jig-Saw Problem - Circles The equation shows the height of a kicked soccer ball, h(d) meters as a function of the horizontal distance, d meters, until it first hits the ground. h(d ) 0.025(d 20) 2 10 a) Graph the function. Include your window choices. Label the axes with height and distance. b) What is the maximum height of the ball? Label this point on the graph. c) What is the horizontal distance of the ball from the kicker when it reaches its maximum height? What characteristic of a parabola does this number represent? d) How far does the ball travel horizontally from when it is kicked until it hits the ground? Label this point on the graph. What is this point called? e) What is the height of the ball when it is 10 m horizontally from the kicker? Label this point on the graph. How did you find this point? f) Would an opposing player positioned under the path of the ball 34 m from the kicker be able to head the ball? Label this point on the graph. Explain how you determined this. g) State the domain and range for the path of the soccer ball. Mathematics 20-2 Quadratic Functions and Equations Page 61 of 96 Jig-Saw Problem - Triangles The sum of two numbers is 60. Their product is a maximum. Determine the numbers. Mathematics 20-2 Quadratic Functions and Equations Page 62 of 96 Jig-Saw Problem - Squares A rectangular lot is bordered on one side by a stream and on the other three sides by 600 m of fencing. The area of the lot is a maximum. Determine the area. Mathematics 20-2 Quadratic Functions and Equations Page 63 of 96 Jig-Saw Problem - Stars A student who wishes to use a computer lab at a local library must buy a membership. The library charges $20 for membership. Four hundred students purchase the membership. The library estimates that for every $4 increase in the membership fee, 40 fewer students will become members. What membership fee will provide the maximum revenue for the library? Mathematics 20-2 Quadratic Functions and Equations Page 64 of 96 M20-2 Lesson 2 Jig Saw Applications Key Mathematics 20-2 Quadratic Functions and Equations Page 65 of 96 Mathematics 20-2 Quadratic Functions and Equations Page 66 of 96 Mathematics 20-2 Quadratic Functions and Equations Page 67 of 96 Mathematics 20-2 Quadratic Functions and Equations Page 68 of 96 Mathematics 20-2 Quadratic Functions and Equations Page 69 of 96 M20-2 Lesson 2 Jig Saw Equation Forms Jig-Saw Problem - Circles Sketch a graph of the following quadratic function and complete the table provided. 𝑦 = 𝑥 2 + 2𝑥 − 8 𝑦 = 𝑥 2 + 2𝑥 − 8 Vertex Maximum or minimum value y-intercept x-intercept(s) Equation of the Axis of Symmetry Domain Range Mathematics 20-2 Quadratic Functions and Equations Page 70 of 96 Jig-Saw Problem - Triangles Sketch a graph of the following quadratic function and complete the table provided. 𝑦 = (𝑥 + 1)2 − 9 𝑦 = (𝑥 + 1)2 − 9 Vertex Maximum or minimum value y-intercept x-intercept(s) Equation of the Axis of Symmetry Domain Range Mathematics 20-2 Quadratic Functions and Equations Page 71 of 96 Jig-Saw Problem - Squares Sketch a graph of the following quadratic function and complete the table provided. 𝑦 = (𝑥 + 4)(𝑥 − 2) 𝑦 = (𝑥 + 4)(𝑥 − 2) Vertex Maximum or minimum value y-intercept x-intercept(s) Equation of the Axis of Symmetry Domain Range Mathematics 20-2 Quadratic Functions and Equations Page 72 of 96 Jig-Saw Problem - Stars Sketch a graph of the following quadratic function and complete the table provided. x -5 -4 -1 0 2 3 y 7 0 -9 -8 0 7 Vertex Maximum or minimum value y-intercept x-intercept(s) Equation of the Axis of Symmetry Domain Range Mathematics 20-2 Quadratic Functions and Equations Page 73 of 96 M20-2 Lesson 2 Jig Saw Equation Forms Key Jig-Saw Problem - Circles Sketch a graph of the following quadratic function and complete the table provided. 𝑦 = 𝑥 2 + 2𝑥 − 8 y = x^2+2x-8 y x 𝑦 = 𝑥 2 + 2𝑥 − 8 (-1, -9) Vertex Maximum or minimum value Minimum y = -9 y-intercept y = -8 x-intercept(s) x = -4, 2 Equation of the Axis of Symmetry Mathematics 20-2 x = -1 Domain 𝑥∈𝑅 Range 𝑦 ≥ −9 Quadratic Functions and Equations Page 74 of 96 Jig-Saw Problem - Triangles Sketch a graph of the following quadratic function and complete the table provided. 𝑦 = (𝑥 + 1)2 − 9 y = x^2+2x-8 y x 𝑦 = (𝑥 + 1)2 − 9 Vertex (-1, -9) Maximum or minimum value y-intercept y = -8 x-intercept(s) x = -4, 2 Equation of the Axis of Symmetry x = -1 Domain 𝑥∈𝑅 Range Mathematics 20-2 Minimum y = -9 𝑦 ≥ −9 Quadratic Functions and Equations Page 75 of 96 Jig-Saw Problem - Squares Sketch a graph of the following quadratic function and complete the table provided. 𝑦 = (𝑥 + 4)(𝑥 − 2) y = x^2+2x-8 y x 𝑦 = (𝑥 + 4)(𝑥 − 2) Vertex (-1, -9) Maximum or minimum value y-intercept y = -8 x-intercept(s) x = -4, 2 Equation of the Axis of Symmetry x = -1 Domain 𝑥∈𝑅 Range Mathematics 20-2 Minimum y = -9 𝑦 ≥ −9 Quadratic Functions and Equations Page 76 of 96 Jig-Saw Problem - Stars Sketch a graph of the following quadratic function and complete the table provided. y = x^2+2x-8 y x -5 -4 -1 0 2 3 y 7 0 -9 -8 0 7 x Vertex (-1, -9) Maximum or minimum value y-intercept y = -8 x-intercept(s) x = -4, 2 Equation of the Axis of Symmetry x = -1 Domain 𝑥∈𝑅 Range Mathematics 20-2 Minimum y = -9 𝑦 ≥ −9 Quadratic Functions and Equations Page 77 of 96 M20-2 Lesson 2 Matching Activity Matching 1 Vertex (2, 1) Mathematics 20-2 Minimum Value at -2 Range 𝑦 ≥ −1 Quadratic Functions and Equations Page 78 of 96 Domain 𝑥 ∈ 𝑅 Range 𝑦 ≥ 3 Equation for axis of symmetry is 𝑥 = −5 Opens down Vertex (-3, -2) Range 𝑦 ≤ −5 Mathematics 20-2 Quadratic Functions and Equations Page 79 of 96 Matching 2 𝑦 = (𝑥 + 3)2 𝑦 = 𝑥2 + 3 𝑦 = −2𝑥 2 𝑦 = 2𝑥 2 𝑦 = (𝑥 − 2)2 + 1 𝑦 = (𝑥 + 2)2 − 1 Mathematics 20-2 Quadratic Functions and Equations Page 80 of 96 𝑦 = (𝑥 − 5)2 + 3 𝑦 = −(𝑥 + 3)2 − 2 𝑦 = −𝑥 2 − 5 x-intercepts are (-1, 0) & (-3, 0) Vertex (-2, -1) x-intercepts are (-1, 0) & (-3, 0) Vertex (-2, -1) Mathematics 20-2 y-intercept is 1 Quadratic Functions and Equations Page 81 of 96 M20-2 Lesson 2 Matching Activity Key This activity is designed to reaffirm students’ knowledge of intercepts, vertex, maximums/minimums, domain, and range. Students work in small groups and match a quadratic function to a corresponding graph or vocabulary word(s). Teachers will need to photocopy Matching 1 and Matching 2 (in different colors) and cut each square out. Each group will receive 24 squares and match them accordingly. Key 𝑦 = (𝑥 + 3)2 𝑦 = 𝑥2 + 3 𝑦 = −2𝑥 2 𝑦 = 2𝑥 2 𝑦 = (𝑥 − 2)2 + 1 ↓ Vertex (2, 1) 𝑦 = (𝑥 + 2)2 − 1 ↓ Minimum Value at -2 Range 𝑦 ≥ −1 𝑦 = −(𝑥 + 3)2 − 2 ↓ Opens down Vertex (-3, -2) 𝑦 = −𝑥 2 − 5 ↓ Range 𝑦 ≤ −5 𝑦 = (𝑥 − 5)2 + 3 ↓ Domain 𝑥 ∈ 𝑅 Range 𝑦 ≥ 3 𝑦 = (𝑥 + 5)2 + 3 ↓ Equation for axis of symmetry is 𝑥 = −5 x-intercepts are (-1, 0) & (-3, 0) Vertex (-2, -1) y-intercept is 1 Mathematics 20-2 Quadratic Functions and Equations Page 82 of 96 M20-2 Lesson 3 Rectangles and Algebra Tiles Completion Assignment Rectangles and Algebra Tiles Polynomial Sketch of Rectangle Grid Factors 2x2+3x+1 x +3 3x +2 3x2 2x 9x 6 (x+3)(x+5) x +3 Mathematics 20-2 2x +3 2x2 3x 6x 9 Quadratic Functions and Equations Page 83 of 96 3x2+13x+4 (6x+3)(x+2) 5x2+8x+3 8x2+18x+9 Mathematics 20-2 Quadratic Functions and Equations Page 84 of 96 M20-2 Lesson 3 Factoring Review Examples Factoring Trinomials Example: 6x2 + 14x - 12 2(3x2 + 7x – 6) Factor Pictorially Mathematics 20-2 GCF First! Factor Symbolically Quadratic Functions and Equations Page 85 of 96 Difference of Squares Example: 27x2 - 75 2(9x2 – 25) Factor Pictorially Mathematics 20-2 GCF First! Factor Symbolically Quadratic Functions and Equations Page 86 of 96 M20-2 Lesson 3 Factoring Review Examples Sample Solutions Mathematics 20-2 Quadratic Functions and Equations Page 87 of 96 Mathematics 20-2 Quadratic Functions and Equations Page 88 of 96 M20-2 Lesson 3 Solving Using the Quadratic Formula In General: The roots (solutions) of the quadratic equation ax2 + bx + c = 0 can be found using the Quadratic Formula: x = -b ± b2 - 4ac 2a Problem 1: Solve the quadratic equation x2 + 5x - 14 = 0 using the quadratic formula. Problem 2: Solve the quadratic equation x2 - 2x - 15 = 0 using the quadratic formula. Problem 3: Solve the quadratic equation 2x 2 + 5x - 12 = 0 using the quadratic formula. Problem 4: Solve the quadratic equation 3x2 + 5x - 2 = 0 using the quadratic formula. Mathematics 20-2 Quadratic Functions and Equations Page 89 of 96 Recall: An entire radical is changed into a mixed radical by factoring the largest perfect square out of the radicand. Problem 5: Simplify the following by changing the entire radicals into mixed radicals. a) 32 6 b) 2+ 8 2 c) 3 - 12 2 d) 9 - 27 6 Problem 6: Solve the quadratic equation 3x 2 + 5x - 11 = 0 using the quadratic formula. Problem 7: Determine the solutions using the Quadratic Formula. a) 4x 2 - 12x + 9 = 0 Mathematics 20-2 b) 2t 2 - 11t + 15 = 0 Quadratic Functions and Equations Page 90 of 96 Problem 8: The height of the Peace Tower in Ottawa is 90 m. If an object is thrown downward at 5 m/s from this height, the time, t seconds, the object takes to reach the ground can be found by solving the equation -4.9t 2 - 5t + 90 = 0 . Determine the time, to the nearest tenth of a second, for the object to hit the ground? Problem 9: Solve: 15x2 - 37x + 20 = 0. Mathematics 20-2 Quadratic Functions and Equations Page 91 of 96 M20-2 Lesson 3 Solving Using the Quadratic Formula Key In General: The roots (solutions) of the quadratic equation ax2 + bx + c = 0 can be found -b ± b2 - 4ac using the Quadratic Formula: x = 2a Problem 1: Solve the quadratic equation x2 + 5x - 14 = 0 using the quadratic formula. a = 1, b = 5, c = -14 x= ( ) ( 5) - 5 ± 2 ( )( - 4 1 -14 () 21 ) = -5 ± 25 + 56 -5 ± 81 -5 ± 9 = = 2 2 2 x = -7, 2 Check ( -7) 2 ( ) (2) + 5 -7 - 14 = 0 0=0 2 () + 5 2 - 14 = 0 0=0 Problem 2: Solve the quadratic equation x2 - 2x - 15 = 0 using the quadratic formula. a = 1, b = -2, c = -15 x= ( ) ( -2) - 4 (1) ( -15) = 2 ± 2 (1) 2 - -2 ± 4 + 60 2 ± 64 2 ± 8 = = 2 2 2 x = -3, 5 Check ( -3) 2 ( ) (5) - 2 -3 - 15 = 0 0=0 2 () - 2 5 -15 = 0 0=0 Problem 3: Solve the quadratic equation 2x 2 + 5x - 12 = 0 using the quadratic formula. a = 2, b = 5, c = -12 x= ( ) ( 5) - 5 ± 2 ( )( ) = -5 ± - 4 2 -12 () 2 2 25 + 96 -5 ± 121 -5 ± 11 = = 4 4 4 x = -4, 3/2 Check ( ) 2 2 ( ) 2 -4 + 5 -4 - 12 = 0 0=0 Mathematics 20-2 æ 3ö æ 3ö 2 ç ÷ + 5 ç ÷ - 12 = 0 è 2ø è 2ø 0=0 Quadratic Functions and Equations Page 92 of 96 Problem 4: Solve the quadratic equation 3x2 + 5x - 2 = 0 using the quadratic formula. a = 3, b = 5, c = -2 x= ( ) (5) - 4 (3) ( -2) = -5 ± 2 ( 3) 2 - 5 ± 25 + 24 -5 ± 49 -5 ± 7 = = 6 6 6 x = -2, 1/3 Check ( ) 2 æ 1ö æ 1ö 3ç ÷ + 5ç ÷ - 2 = 0 è 3ø è 3ø 0=0 ( ) 2 3 -2 + 5 -2 - 2 = 0 0=0 Problem 5: Simplify the following by changing the entire radicals into mixed radicals. 32 4 2 2 2 = = 6 6 3 a) c) 3 - 12 3 - 2 3 = 2 2 b) 2+ 8 2+2 2 = = 1+ 2 2 2 d) 9 - 27 9 - 3 3 3 - 3 = = 6 6 2 Problem 6: Solve the quadratic equation 3x 2 + 5x - 11 = 0 using the quadratic formula. a = 3, b = 5, c = -11 x= ( ) ( 5) - 5 ± 2 ( ) ( ) = -5 ± - 4 3 -11 () 23 25 + 132 -5 ± 157 = 6 6 Problem 7: Determine the solutions using the Quadratic Formula. a) 4x 2 - 12x + 9 = 0 a = 4, b = -12, c = 9 x= ( ) ( -12) 2 ( 4) - -12 ± 2 ( ) ( ) = 12 ± -4 4 9 144 - 144 12 ± 0 = 8 8 x = 3/2 Check 2 æ 3ö æ 3ö 4 ç ÷ - 12 ç ÷ + 9 = 0 è 2ø è 2ø 0=0 b) 2t 2 - 11t + 15 = 0 a = 2, b = -11, c = 15 Mathematics 20-2 Quadratic Functions and Equations Page 93 of 96 x= ( ) ( -11) - 4 (2) (15) = 11± 2 ( 2) 2 - -11 ± 121- 120 11± 1 = 4 4 x = 5/2, 3 Check 2 æ 5ö æ 5ö 2 ç ÷ - 11ç ÷ + 15 = 0 è 2ø è 2ø 0=0 () () 2 2 3 - 11 3 + 15 = 0 0=0 Problem 8: The height of the Peace Tower in Ottawa is 90 m. If an object is thrown downward at 5 m/s from this height, the time, t seconds, the object takes to reach the ground can be found by solving the equation -4.9t 2 - 5t + 90 = 0 . Determine the time, to the nearest tenth of a second, for the object to hit the ground? -4.9t 2 - 5t + 90 = 0 a = -4.9, b = -5, c = 90 x= ( ) ( -5) - 4 ( -4.9) (90) = 5 ± 2 ( -4.9) 2 - -5 ± 25 + 1764 5 ± 1789 = -9.8 -9.8 x = -4.826 …, 3.805 … Since x > 0, x = 3.8 (10th) Problem 9: Solve: 15x2 - 37x + 20 = 0. a = 15, b = -37, c = 20 x= ( ) ( -37) - 4 (15) (20) = 37 ± 2 (15) - -37 ± 2 1369 - 1200 37 ± 169 37 ± 13 = = 30 30 30 x = 4/5, 5/3 Check 2 æ 4ö æ 4ö 15 ç ÷ - 37 ç ÷ + 20 = 0 è 5ø è 5ø 0=0 Mathematics 20-2 2 æ 5ö æ 5ö 15 ç ÷ - 37 ç ÷ + 20 = 0 è 3ø è 3ø 0=0 Quadratic Functions and Equations Page 94 of 96 M20-2 Lesson 3 Solving Equations Questions Group 1 a) x2 - 6x + 8 = 0 b) 2t2 - 6t + 5 = 0 c) 3x2 + 15x = 0 d) x2 - 36 = 0 Group 6 a) x2 - x - 6 = 0 b) 4x2 + 31x - 8 = 0 c) 2x2 - 22x = 0 d) x2 - 4 = 0 Group 2 a) x2 - x - 6 = 0 b) 4x2 + 31x - 8 = 0 c) 2x2 - 22x = 0 d) x2 - 4 = 0 Group 7 a) x2 + 12x + 32 = 0 b) 2x2 - 3x - 9 = 0 c) 3x2 + 27x = 0 d) x2 - 121 = 0 Group 3 a) t2 + 4t - 12 = 0 b) 4t2 + 9t - 9 = 0 c) 4x2 - 8x = 0 d) x2 - 144 = 0 Group 8 a) x2 + 8x - 180 = 0 b) 3x2 - 5x + 2 = 0 c) 8x2 - 56x = 0 d) x2 - 100 = 0 Group 4 a) a2 + 4a - 21 = 0 b) 2t2 + 5t - 12 = 0 c) -5x2 + 25x = 0 d) x2 - 25 = 0 Group 9 a) x2 - 3x + 2 = 0 b) 3x2 - 7x + 2 = 0 c) -6x2 + 12x = 0 d) x2 - 1 = 0 Group 5 a) x2 + 2x + 1 = 0 b) 2x2 - 11x - 6 = 0 c) -7x2 - 21x = 0 d) x2 - 49 = 0 Mathematics 20-2 Quadratic Functions and Equations Page 95 of 96 M20-2 Lesson 3 Solving Equations Questions Key Group 1 a) 2, 4 b) 1.5, 0.5 c) 0, -5 d) +6, -6 Group 6 a) 3, -5 b) -1, 2.5 c) 0, 7 d) +3, -3 Group 2 a) 3, -2 b) - 8, 0.25 c) 0, 11 d) +2, -2 Group 7 a) -4, -8 b) 3, -1.5 c) 0, -9 d) +11, -11 Group 3 a) -6, 2 b) -3, 0.75 c) 0, 2 d) +12, -12 Group 8 a) 10, -18 b) 2/3, 1 c) 0, 7 d) +10, -10 Group 4 a) -7, 3 b) -4, 1.5 c) 0, 5 d) +5, -5 Group 9 a) 2, 1 b) 1/3, 2 c) 0, 2 d) +1, -1 Group 5 a) -1 b) -0.5, 6 c) 0, -3 d) +7, -7 Mathematics 20-2 Quadratic Functions and Equations Page 96 of 96