MATHEMATICS 20-2 Radicals 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 Mathematics 20-2 Radicals Page 2 of 125 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 1. How do you find the area of a triangle? (let me count the ways) Teacher Notes for Transfer Task Transfer Task Rubric Possible Solution 7 9 15 18 2. Spiralling Out of Control Teacher Notes for Transfer Task Transfer Task Rubric Possible Solution 44 45 52 55 2. Radical Race Teacher Notes for Transfer Task Transfer Task Rubric Possible Solution 65 69 85 87 STAGE 3 LEARNING PLANS Lesson #1 What Should I Remember? 90 Lesson #2 What’s with all the Letters? 94 Lesson #3 Let’s Play Operation (Operations on Radicals) 97 Lesson #4 Radical Issues (Solving Radical Equations) 103 Appendix – Worksheets/Keys Mathematics 20-2 108 Radicals Page 3 of 125 Mathematics 20-2 Radicals STAGE 1 Desired Results Big Idea: Understanding radicals will further develop student’s sense of exact values, and enhance their ability to simplify expressions and solve equations. Implementation note: Post the BIG IDEA in a prominent place in your classroom and refer to it often. Enduring Understandings: Students will understand … There are restrictions on values for the variable in a radical. Some equations have extraneous roots, and why. There are appropriate forms of communications in mathematics. Radicals are more precise efficient, concise and accurate. Operations can be performed on radicals, as with other numbers and algebraic expressions. Essential Questions: Why are extraneous roots produced? Why is there a restriction on the domain? Why does your calculator say ERROR on ? When is an exact solution required? Under what circumstances would a mixed radical or an entire radical be appropriate? When is x > y ? When would you use radicals? Implementation note: Ask students to consider one of the essential questions every lesson or two. Has their thinking changed or evolved? Mathematics 20-2 Radicals Page 4 of 125 Knowledge: Enduring Understanding List enduring understandings (the fewer the better) Specific Outcomes List the reference # from the Alberta Program of Studies Students will know … Students will understand… There are restrictions on values for the variable in a radical. *NL 3.6 There are appropriate forms of communications in mathematics. NL 3.2, 3.3, 3.5 Radicals are more precise, efficient, concise and accurate. NL 4.5 Operations can be performed on radicals, as with other numbers or algebraic expressions. I*NL when the expression is simplified when it is appropriate to use an exact value versus a rounded decimal Students will know … Students will understand… the square root of a negative number is not a real number Students will know … Students will understand… Students will know … Students will understand… Description of Knowledge The paraphrased outcome that the group is targeting NL 3.4 what like terms are the rules for operations on radicals = Number and Logic Mathematics 20-2 Radicals Page 5 of 125 Skills: Enduring Understanding List enduring understandings (the fewer the better) Specific Outcomes List the reference # from the Alberta Program of Studies Students will be able to… Students will understand… There are restrictions on values for the variable in a radical. *NL 3.6 Some equations have extraneous roots, and why. NL 4.1, 4.3 There are appropriate forms of communications in mathematics. NL 3.2, 3.3, 3.4, 3.5, 4.5 Radicals are more precise, efficient, concise and accurate. determine any restrictions on values for the variable in a radical equation verify, by substitution, that the values determined in solving a radical equation are roots of the equation simplify radical expressions with numerical or variable radicands rationalize the monomial denominator of a radical expression model a situation with a radical equation Students will be able to… Students will understand… identify values of the variable for which the radical expression is defined Students will be able to… Students will understand… Students will be able to… Students will understand… Description of Skills The paraphrased outcome that the group is targeting answer questions with exact values NL3, NL4 Students will understand… Students will be able to… Operations can be performed on radicals, as with other numbers or algebraic expressions. I*NL NL 3.4, 4.2 perform operations with radicals solve radical equations to determine the roots = Number and Logic Implementation note: Teachers need to continually ask themselves, if their students are acquiring the knowledge and skills needed for the unit. Mathematics 20-2 Radicals Page 6 of 125 STAGE 2 1 Assessment Evidence Desired Results Desired Results Teacher Notes There are three transfer tasks to evaluate student understanding of the concepts relating to radicals. A photocopy-ready version of each transfer task is included in this section. 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. The first is not as open ended as many of the other transfer tasks have been. Glossary absolute value – Represents how far the number is from zero entire radical – A radical with a coefficient of 1 [Math 20-2 (Nelson: page 515)] extraneous root – A number obtained in the process of solving an equation that does not satisfy the equation mixed radicals – A radical with a coefficient other than 1 [Math 20-2 (Nelson: page 516)] perfect square – A number, from a given number system, that can be expressed as the square of a number from the same number system principal square root – The positive number square root rationalize the denominator – The process used to write a radical expression that contains a radical denominator into an equivalent expression with a rational denominator [Math 20-2 (Nelson: page 517)] restrictions – The values of a the variable in an expression that ensure it to be defined [Math 20-2 (Nelson: page 517)] secondary square root – The negative number square root Glossary hyperlinks redirect you to the Learn Alberta Mathematics Glossary (http://www.learnalberta.ca/content/memg/index.html). Some terms can be found in more than one division. Some terms have animations to illustrate meanings. Mathematics 20-2 Radicals Page 7 of 125 Transfer Task 1: How do you find the area of a triangle? (let me count the ways) When students choose three squares to create a triangle, the intention is that students may reuse a square if they wish. They do not have to use three different squares. (Student assessment Part C) Some combinations will not produce a triangle, i.e. 12, 12, 48 or 12, 12, 72. Students may need to be reminded to show their work in finding the semiperimeter (half the perimeter) when they use Heron’s formula. Students will need to review the product of binomial conjugates (ax - b) (ax + b) = a x 2 2 - b2 ) This will save them significant amounts of time, when they recognize it in the problem. 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 Radicals Page 8 of 125 How do you find the area of a triangle? - Student Assessment Task There are many different ways to find the area of a triangle. You may recall that the 1 area of a triangle is A = bh , but this is only one of several different formulae for 2 achieving the same value. In fact it is often easier to use a different formula when the information you have is not conducive to the regular formula. A. To start, find the area of the following equilateral triangles. 2 2 4 4 2 4 To use the formula A = 1 bh you will first need to find its altitude. Use the following 2 diagram as your guide. 2 2 h 1 1 How do you find the area of a triangle? - Student Assessment Task Based on your above work, if the length of the side of the equilateral triangle is 2n, then find expressions for both the height and the area of the triangle. Verify this with an equilateral triangle with a side length of 6 or 8. B. Many other formulas have been developed to find the area of a triangle. The following two formulas use just the side lengths of a triangle to determine its area. ( )( )( ) A = s s - a s - b s - c , where s = a c 1 2 2 æ a2 + c 2 - b2 ö A= a c -ç ÷ø 2 2 è a + b +c 2 2 The first equation given above is called Heron’s equation and it was published in 60 AD. In this equation s is called the semiperimeter (half of the perimeter of the triangle). The second formula was developed independently by the Chinese and was published in 1247 AD. Both the equations are useful, especially for oblique triangles because all you need to find the area of the triangle is the length of its sides. http://en.wikipedia.org/wiki/Heron%27s_formula How do you find the area of a triangle? - Student Assessment Task Verify these equations with one of the triangles you worked with originally. Now, if you are given that the area of a triangle is 14 5 units2, then use the formula 1 2 2 æa2 +c 2 - b2 ö A= a c -ç ÷ø 2 2 è 2 to find the possible exact values of the lengths of side b given that a = 12 and c = 7. The first step has been completed for you. b 7 12 12 1 2 2 æ 72 + 122 - b 2 ö 14 5 = 7 12 - ç ÷ø 2 2 è 2 How do you find the area of a triangle? - Student Assessment Task C. Consider four squares with areas of 12, 27, 48 and 72 u2. If we take three of these squares and connect their vertices as shown below… 48 u 2 12 u 2 72 u 2 The lengths of sides of each of the squares can be determined, hence allowing us to determine the area of the triangle contained between. Show that the area of the triangle in the above diagram is 3 15 u 2, using Heron’s Formula. How do you find the area of a triangle? - Student Assessment Task Given the area, determine the smallest altitude in that triangle in simplest mixed 1 radical form, rationalizing the denominator when necessary. (Hint: use A = bh ) 2 D. Now using any three of the above squares (duplicating squares if you wish) enclose a triangle of your own making and determine its area using Heron’s formula, and its smallest altitude. You must connect the vertices to create a triangle. Some combinations won’t work. Note: this means that students can reuse a square if they wish to, but not all combinations work together to create a triangle. How do you find the area of a triangle? - Student Assessment Task Glossary absolute value – Represents how far the number is from zero entire radical – A radical with a coefficient of 1 [Math 20-2 (Nelson: page 515)] extraneous root – A number obtained in the process of solving an equation that does not satisfy the equation mixed radicals – A radical with a coefficient other than 1 [Math 20-2 (Nelson: page 516)] perfect square – A number, from a given number system, that can be expressed as the square of a number from the same number system principal square root – The positive square root rationalize the denominator – The process used to write a radical expression that contains a radical denominator into an equivalent expression with a rational denominator [Math 20-2 (Nelson: page 517)] restrictions – The values of a the variable in an expression that ensure it to be defined [Math 20-2 (Nelson: page 517)] secondary square root – The negative square root Glossary hyperlinks redirect you to the Learn Alberta Mathematics Glossary (http://www.learnalberta.ca/content/memg/index.html). Some terms can be found in more than one division. Some terms have animations to illustrate meanings. Assessment Mathematics 20-2 How do you find the area of a triangle? Rubric Component Description of Requirements - Part A - Altitude and Area are determined for the two given triangles - Algebraic expressions for the altitude and area are determined - Expression is verified - Mathematical Content Assessment IN 1 2 3 4 Part B Original area is verified using the two new formulas Determines the possible lengths of the sides of the triangle IN 1 2 3 4 - Part C Determines semiperimeter value Shows how area is 3√15𝑢2 Determines smallest altitude in proper form IN 1 2 3 4 - Part D Creates a valid triangle Determines area and smallest altitude IN 1 2 3 4 - Level Excellent Criteria 4 Math All required Content elements Part A are present and correct Proficient 3 All required elements are present but may contain minor errors Math Content Part B All required elements are present and correct All required elements are present but may contain minor errors Math Content Part C All required elements are present and correct All required elements are present but may contain minor errors Math Content Part D All required elements are present and correct All required elements are present but may contain minor errors Adequate 2 Some required elements are missing, or contain major errors Some required elements are missing, or contain major errors Some required elements are missing, or contain major errors Some required elements are missing, or contain major errors 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 Most required elements are missing or incorrect No score is awarded as there is no evidence given When work is judged to be limited or insufficient, the teacher makes decisions about appropriate intervention to help the student improve Glossary entire radical – A radical with a coefficient of 1 [Math 20-2 (Nelson: page 515)] mixed radicals – A radical with a coefficient other than 1 [Math 20-2 (Nelson: page 516)] perfect square – A number, from a given number system, that can be expressed as the square of a number from the same number system principal square root – The positive square root rationalize the denominator – The process used to write a radical expression that contains a radical denominator into an equivalent expression with a rational denominator [Math 20-2 (Nelson: page 517)] restrictions – The values of a the variable in an expression that ensure it to be defined [Math 20-2 (Nelson: page 517)] secondary square root – The negative square root Glossary hyperlinks redirect you to the Learn Alberta Mathematics Glossary (http://www.learnalberta.ca/content/memg/index.html). Some terms can be found in more than one division. Some terms have animations to illustrate meanings. Possible Solution to How do you find the area of a triangle? There are many different ways to find the area of a triangle. You may recall that the 1 area of a triangle is A = bh , but this is only one of several different formulae for 2 achieving the same value. In fact it is often easier to use a different formula when the information you have is not conducive to the regular formula. A. To start, find the area of the following equilateral triangles. 2 2 4 4 2 4 1 bh you will first need to find its altitude. Use the 2 following diagram as your guide. To use the formula A = 2 2 h 1 1 Sample Solution 1 Mathematics 20-2 Radicals Page of 125 18 Sample Solution 2 Mathematics 20-2 Radicals Page of 125 19 Based on your above work, if the length of the side of the equilateral triangle is 2n, then find expressions for both the height and the area of the triangle. Verify this with an equilateral triangle with a side length of 6 or 8. Sample Solution 1 Sample Solution 2 Mathematics 20-2 Radicals Page of 125 20 B. Many other formulas have been developed to find the area of a triangle. The following two formulas use just the side lengths of a triangle to determine its area. ( )( )( ) A = s s - a s - b s - c , where s = a c 1 2 2 æa2 +c 2 - b2 ö A= a c -ç ÷ø 2 2 è a + b +c 2 2 The first equation given above is called Heron’s equation and it was published in 60 AD. In this equation s is called the semiperimeter (half of the perimeter of the triangle). The second formula was developed independently by the Chinese and was published in 1247 AD. Both the equations are useful, especially for oblique triangles because all you need to find the area of the triangle is the length of its sides. http://en.wikipedia.org/wiki/Heron%27s_formula Mathematics 20-2 Radicals Page of 125 21 Verify these equations with one of the triangles you worked with originally. Sample Solution 1 Sample Solution 2 Now, if you are given that the area of a triangle is 14 5 units2, then use the formula 1 2 2 æa2 +c 2 - b2 ö A= a c -ç ÷ø 2 2 è 2 to find the possible exact values of the lengths of side b given that a = 12 and c = 7. The first step has been completed for you. b 7 12 12 Sample Solution 1 Sample Solution 2 Mathematics 20-2 Radicals Page of 125 23 D. Consider four squares with areas of 12, 27, 48 and 72 u2. If we take three of these squares and connect their vertices as shown below… 48 u 2 12 u 2 72 u 2 The lengths of sides of each of the squares can be determined, hence allowing us to determine the area of the triangle contained between. Show that the area of the triangle in the above diagram is 3 15 u 2, using Heron’s Formula. Sample Solution 1 Mathematics 20-2 Radicals Page of 125 24 Sample Solution 2 Mathematics 20-2 Radicals Page of 125 25 Given the area, determine the smallest altitude in that triangle in simplest mixed 1 radical form, rationalizing the denominator when necessary. (Hint: use A = bh ) 2 Sample Solution 1 Sample Solution 2 D. Now using any three of the above squares (duplicating squares if you wish) enclose a triangle of your own making and determine its area using Heron’s formula, and its smallest altitude. (you must create a triangle with some area, which means some combinations won’t work) Sample Solution 1 Mathematics 20-2 Inductive and Deductive Reasoning Page 27 of 125 Sample Solution 2 Mathematics 20-2 Inductive and Deductive Reasoning Page 28 of 125 Sample Solution 3 Mathematics 20-2 Inductive and Deductive Reasoning Page 29 of 125 Sample Solution 4 Mathematics 20-2 Inductive and Deductive Reasoning Page 30 of 125 Sample Solution 5 Mathematics 20-2 Inductive and Deductive Reasoning Page 31 of 125 Sample Solution 6 Mathematics 20-2 Inductive and Deductive Reasoning Page 32 of 125 Sample Solution 7 Mathematics 20-2 Inductive and Deductive Reasoning Page 33 of 125 Sample Solution 8 Mathematics 20-2 Inductive and Deductive Reasoning Page 34 of 125 Sample Solution 9 Mathematics 20-2 Inductive and Deductive Reasoning Page 35 of 125 Sample Solution 10 Mathematics 20-2 Inductive and Deductive Reasoning Page 36 of 125 Sample Solution 11 Mathematics 20-2 Inductive and Deductive Reasoning Page 37 of 125 Sample Solution 12 Mathematics 20-2 Inductive and Deductive Reasoning Page 38 of 125 Sample Solution 13 Mathematics 20-2 Inductive and Deductive Reasoning Page 39 of 125 Sample Solution 14 Mathematics 20-2 Inductive and Deductive Reasoning Page 40 of 125 Sample Solution 15 Mathematics 20-2 Inductive and Deductive Reasoning Page 41 of 125 Sample Solution 16 Mathematics 20-2 Inductive and Deductive Reasoning Page 42 of 125 Sample Solution 17 Note: this means that students can reuse a square if they wish to, but all combinations work together to create a triangle. Mathematics 20-2 Inductive and Deductive Reasoning Page 43 of 125 Transfer Task 2: Spiralling Out of Control Teacher Notes Students may need graph paper provided for Part B. Students may need some help in constructing the radical spiral. Remember that they are adding isosceles triangles at every step, so this is not the same as the Pythagorean spiral in which the outer edge always has a length of one. The solution to the intersection of the line and circle in Part C involves solving a quadratic equation by factoring. This is beyond the scope of the curriculum. Glossary absolute value – Represents how far the number is from zero entire radical – A radical with a coefficient of 1 [Math 20-2 (Nelson: page 515)] extraneous root – A number obtained in the process of solving an equation that does not satisfy the equation Fibonacci number sequence- The sequence obtained when each term is the sum of the previous two terms and the first two terms are 0 and 1 (alternatively the first two terms could be 1 and 1) mixed radicals – A radical with a coefficient other than 1 [Math 20-2 (Nelson: page 516)] perfect square – A number, from a given number system, that can be expressed as the square of a number from the same number system principal square root – The positive square root rationalize the denominator – The process used to write a radical expression that contains a radical denominator into an equivalent expression with a rational denominator [Math 20-2 (Nelson: page 517)] restrictions – The values of a the variable in an expression that ensure it to be defined [Math 20-2 (Nelson: page 517)] secondary square root – The negative square root Glossary hyperlinks redirect you to the Learn Alberta Mathematics Glossary (http://www.learnalberta.ca/content/memg/index.html). Some terms can be found in more than one division. Some terms have animations to illustrate meanings. Mathematics 20-2 Inductive and Deductive Reasoning Page 44 of 125 Spiralling Out of Control - Student Assessment Task Take a moment to contemplate your math education. Do you feel, as our title suggests, that it is spiralling out of control? If it does, you may find comfort in knowing a bit more about spirals. Radical Spirals Part A. To introduce how this type of a spiral can be drawn we will start with a basic right triangle. We will use grid paper to draw these, because it will be far easier to count out our lengths and draw in our perpendicular lines. Notice that the two legs of this triangle are both 1 unit in length. The hypotenuse is 2 units in length. Now draw another isosceles right triangle on top of this one using its hypotenuse as one of the legs as shown. Mathematics 20-2 Inductive and Deductive Reasoning Page 45 of 125 Spiralling Out of Control - Student Assessment Task In this particular task we will always be adding isosceles right triangles no matter what right triangle we begin with. Now we repeat this process on the triangle we just created as follows. Remember that the right angle is always created at the outer end of the previous triangle. And this continues on and on until you are no longer able to add triangles without overlapping your previous work. For simplicity we will restrict our work so that no triangle will lie adjacent to the original. Mathematics 20-2 Inductive and Deductive Reasoning Page 46 of 125 Spiralling Out of Control - Student Assessment Task From the previous diagram determine a simplified expression for the length of the spiral, where its length is the sum of the outer, bolded segments. Part B. Now, using graph paper, draw your own initial right triangle. It can have side lengths of 1 and 3, 2 and 3, 1 and 2… whatever you like; only don’t make it too big as you will quickly run out of room. It will also help to orient your triangle so that the longest leg is running vertically. Continue the process again, adding isosceles right triangles on the hypotenuse of your initial triangle. Complete this process for at least three more triangles. Determine a simplified expression for the length of each of the spirals you generated. Spiralling Out of Control - Student Assessment Task Now, after considering the expressions from the previous diagrams make a generalization about the length of a spiral. Golden Spiral Part C. Consider the Golden Spiral. Joining quarter-circles, whose radii are all consecutive values in the Fibonacci sequence, as follows, creates it. Recall that a Fibonacci sequence is 1, 1, 2, 3, 5, 8, 13, … Each value is the sum of the previous two terms. Spiralling Out of Control - Student Assessment Task Now let’s sketch both of these graphs on the same grid. If we now consider just a portion of the golden spiral, we can consider it the quarter of a circle with the equation y = 25 - x 2 , x ³ 0. The extension of one of these segments of the radical spiral, with the equation y = x + 1, will intersect that portion of the circular part of the golden spiral as shown below. Spiralling Out of Control - Student Assessment Task Now let’s look at these two curves specifically and extended. To make things a little more straight forward let’s remove the restriction on the domain of the equation of the circle and just look at the two functions y = 25 - x 2 , and y = x + 1. You need to find the point of intersection of these two functions by solving this system. The first step is done for you. x + 1= 25 - x 2 Spiralling Out of Control - Student Assessment Task Consider the graph provided above and compare it to your algebraic work. Do you notice any discrepancies? Comment here. Explain why your algebraic work may have provided more solutions than you are seeing on the graph. Assessment Mathematics 20-2 Spiralling Out of Control Rubric . Component Description of Requirements - Part A - Determines length of radical spiral in proper form Assessment IN 1 2 - Part B Draws 3 radical spirals Determines total length of each of the spirals Makes generalization based on results of findings IN 1 2 3 4 - Part C Determines solution to radical equation IN 1 2 3 4 Presentation of Data - Part B Spirals are properly and neatly drawn IN 1 2 Explanation of Findings - Part C Explains existence of and reasons for extraneous roots IN 1 2 3 4 Mathematical Content Level Criteria Math Content Part A Excellent 4 Proficient 3 Math Content Part B All required elements are present and correct All required elements are present but may contain minor errors Adequate 2 All required elements are present and correct Some required elements are missing, or contain major errors Math All required All required Some Content elements elements required Part C are present are present elements and correct but may are contain missing, or minor contain errors major errors Presents Presentation Data of data is Part B clear, precise and accurate Explains Provides Provides Provides Findings insightful logical explanations Part C explanations explanations that are complete but vague Limited 1 Some required elements are missing or incorrect 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 No score is awarded as there is no evidence given Presentation Presentation of of data is data is vague and incomprehensible inaccurate Provides No explanation is explanations provided that are incomplete or confusing. Glossary entire radical – A radical with a coefficient of 1 [Math 20-2 (Nelson: page 515)] extraneous root – A number obtained in the process of solving an equation that does not satisfy the equation mixed radicals – A radical with a coefficient other than 1 [Math 20-2 (Nelson: page 516)] perfect square – A number, from a given number system, that can be expressed as the square of a number from the same number system principal square root – The positive number square root restrictions – The values of a the variable in an expression that ensure it to be defined [Math 20-2 (Nelson: page 517)] secondary square root – The negative number square root Glossary hyperlinks redirect you to the Learn Alberta Mathematics Glossary (http://www.learnalberta.ca/content/memg/index.html). Some terms can be found in more than one division. Some terms have animations to illustrate meanings. Possible Solution to Spiralling Out of Control Spiralling Out of Control - Key Take a moment to contemplate your math education. Do you feel, as our title suggests, that it is spiralling out of control? As it does so, you may find comfort in knowing a bit more about spirals. Radical Spirals Part A. To introduce how this kind of a spiral can be drawn we will start with a basic right triangle. We will use grid paper to draw these, because it will be far easier to count out our lengths and draw in our perpendicular lines. Notice that the two legs of this triangle are both 1 unit in length. The hypotenuse is √2 units in length. Now draw another isosceles right triangle on top of this one using its hypotenuse as one of the legs as shown. Mathematics 20-2 Inductive and Deductive Reasoning Page 55 of 125 Spiralling Out of Control - Key In this particular task we will always be adding isosceles right triangles no matter what right triangle we begin with. Now we repeat this process on the triangle we just created as follows. Remember that the right angle is always created at the outer end of the previous triangle. And this continues on and on until you are no longer able to add triangles without overlapping your previous work. For simplicity we will restrict our work to not even lie adjacent to the original. Calculations: Spiralling Out of Control - Key From that picture determine a simplified expression for the length of the spiral, where its length is the sum of the outer, bolded segments. Part B. Now, using graph paper, draw your own initial right triangle. It can have side lengths of 1 and 3, 2 and 3, 1 and 2… whatever you like; only don’t make it too big, as you will quickly run out of room. It will also help to orient your triangle so that the longest leg is running vertically. Continue the process again, adding isosceles right triangles on the hypotenuse of your initial triangle. Complete this process for at least three more triangles. Determine a simplified expression for the length of each of the spirals you generated. Starting first triangle with 2 & 3 Starting first triangle with 1 & 3 Starting first triangle with 1 & 4 Spiralling Out of Control - Key Now, after considering the expressions you have written make a generalization about the length of a spiral. Golden Spiral Part C. Now recall the Golden Spiral. Joining quarter-circles, whose radii are all consecutive values in the Fibonacci sequence, as follows, creates it. Recall that a Fibonacci sequence is 1, 1, 2, 3, 5, 8, 13, … Each value is the sum of the previous two terms. Spiralling Out of Control - Key Now let’s sketch both of these graphs on the same grid. If we now consider just a portion of the golden spiral, we can consider it the quarter of a circle with the equation y = 25 - x 2 , x ³ 0. The extension of one of these segments of the radical spiral, with the equation y = x + 1, will intersect that portion of the circular part of the golden spiral as shown below. Spiralling Out of Control - Key Now let’s look at these two curves specifically and extended. Now, to make things a little more straight forward let’s remove the restriction on the domain of the equation of the circle and just look at the two functions y = 25 - x 2 , and y = x + 1. You need to find the point of intersection of these two functions by solving this system. The first step is done for you. Spiralling Out of Control - Key Consider the graph provided above and compare it to your algebraic work. Do you notice any discrepancies? Comment here. Explain why your algebraic work may have provided more solutions than you are seeing on the graph. Transfer Task 3: Radical Race Teacher Notes The third transfer task is an option for the end of the unit on radicals (Outcomes 3 and 4). The goal of this task is to have the students practice all skills learned in the unit. The race is composed of 11 question cards, each one in a multiple choice format. The task the students are given is to answer the questions in a given order and choose the next suitable location for subsequent clues, similar to a treasure hunt. The task is designed to work at any school. The teacher will choose the 40 locations and write them on the location list. This list, along with a map of the school will be given to the students. Of the 40 locations, the teacher chooses 11 locations for the correct corresponding answers. The teacher places the clues in a treasure hunt format. There is one clue per card so that the students can clearly show their math processes for each question. The task design allows completion by individuals or groups depending upon class dynamics and teacher preferences. It is advised that teachers build the treasure hunt carefully, ensuring that they clearly record the locations for each clue on their version of the clue cards. The correct answers are marked with a double asterisk. When building the race, choose locations for the correct answers that you want students to access. The other 30 locations are designed as distracters. Question card 11 requires solving a radical equation involving squaring a binomial. The textbook has no questions like this but it was felt that with the skill learned in 10C that this would be appropriate. The rubric focuses on the calculations and the explanations supporting these calculations. Teacher Materials Question Cards with space for solutions Location list School map Answer key Pencil or pens Rules No running No loud noises coming from group Justify all answers mathematically Mathematics 20-2 Inductive and Deductive Reasoning Page 65 of 125 Assessment: Correct answers recorded for all 11 questions with worked out solutions Self assessment Mathematics 20-2 Inductive and Deductive Reasoning Page 66 of 125 Location List: Location 1: Location 11: Location 21: Location 31: Location 2: Location 12: Location 22: Location 32: Location 3: Location 13: Location 23: Location 33: Location 4: Location 14: Location 24: Location 34: Location 5: Location 15: Location 25: Location 35: Location 6: Location 16: Location 26: Location 36: Location 7: Location 17: Location 27: Location 37: Location 8: Location 18: Location 28: Location 38: Location 9: Location 19: Location 29: Location 39: Location 10: Location 20: Location 30: Location 40: Mathematics 20-2 Inductive and Deductive Reasoning Page 67 of 125 Teacher Notes on Questions Cards: Card 1: Outcome 3: Achievement indicator 3.2 Express an entire radical with a numerical radicand as mixed radical Card 2: Outcome 3: Achievement indicator 3.1 Comparing and ordering radical expression with numerical radicands Card 3: Outcome 3: Achievement indicator 3.3 Express a mixed radical with a numerical radicand as an entire radical. Card 4: Outcome 3: Achievement indicator 3.4 Perform one or more operations to simplify radical expressions with numerical or variable radicands. Card 5: Outcome 3: Achievement indicator 3.4 – It was felt that this aspect of the curriculum warranted more than one question. Perform one or more operations to simplify radical expressions with numerical or variable radicands. Card 6: Outcome 3: Achievement indicator 3.5 Rationalize the monomial denominator of a radical expression. Card 7: Outcome 4: Achievement indicator 4.1 Determine any restrictions on values for the variable in a radical equation. Card 8: Outcome 4: Achievement indicator 4.2 Determine algebraically, the roots of a radical equation Card 9: Outcome 4: Achievement indicator 4.3 Verify, by substitution, that the values determined in solving a radical equation are roots of an equation. Card 10: Outcome 4: Achievement indicator 4.5 Solve problems by modeling a situation with a radical equation and solving the equation. Card 11: Outcome 4: Achievement indicator 4.4 Explain why some roots determined in solving a radical equation are extraneous. Note: Outcome 3: Achievement indicator 3.6 was not included as it was felt that the concept was sufficiently covered with achievement indicator 4.1 Mathematics 20-2 Inductive and Deductive Reasoning Page 68 of 125 Glossary absolute value – Represents how far the number is from zero entire radical – A radical with a coefficient of 1 [Math 20-2 (Nelson: page 515)] extraneous root – A number obtained in the process of solving an equation that does not satisfy the equation mixed radicals – A radical with a coefficient other than 1 [Math 20-2 (Nelson: page 516)] perfect square – A number, from a given number system, that can be expressed as the square of a number from the same number system principal square root – The positive square root rationalize the denominator – The process used to write a radical expression that contains a radical denominator into an equivalent expression with a rational denominator [Math 20-2 (Nelson: page 517)] restrictions – The values of a the variable in an expression that ensure it to be defined [Math 20-2 (Nelson: page 517)] secondary square root – The negative square root Glossary hyperlinks redirect you to the Learn Alberta Mathematics Glossary (http://www.learnalberta.ca/content/memg/index.html). Some terms can be found in more than one division. Some terms have animations to illustrate meanings. Mathematics 20-2 Inductive and Deductive Reasoning Page 69 of 125 Transfer Task 3: Radical Race - Student Assessment Task CARD 1: Express each of the following as an entire radical. i) 2 13 ii) 3 6 iii) 4 5 iv) 5 2 1. 26, 18, 20, 10 Go to location one 2. 15, 9, 9, 9 Go to location two 3. 11, 3, 1, -3 Go to location three 4. 52, 54, 80, 50 Go to location four Transfer Task 3: Radical Race - Student Assessment Task CARD 2: Arrange the following in order from least to greatest. i) 2 13 ii) 3 6 iii) 4 5 iv) 5 2 1. 2 13, 3 6, 4 5, 5 2 Go to location five 2. 2 13, 5 2, 3 6, 4 5 Go to location six 3. 5 2, 2 13, 3 6, 4 5 Go to location seven 4. 2 13, 4 5, 5 2, 3 6 Go to location eight Transfer Task 3: Radical Race - Student Assessment Task Card 3: Convert the following mixed radicals to entire radical. iii) 2 x3 a2 a x 5 xy iv) 3xy 3 3 2z 4 i) ii) 1. 4 x 3 , a 3 , x 6 y , 3 27x 3 y 9z 4 Go to location nine 2. 4 x 3 , a 5 , x 11y , 3 27x 3 y 9z 4 Go to location ten 3. 4 x 3 , a 3 , x 11y , 3 27x 3 y 9z 4 Go to location eleven 4. 4 x 3 , a 5 , x 11y , 3 54x 3 y 9z 4 Go to location twelve Transfer Task 3: Radical Race - Student Assessment Task Card 4: Simplify the following expression by combining like radicals 3 5 1 -5 128 + 848 + 50 4 4 2 1. Go to location thirteen 2. 41 2 -36 2 - 5 3 3. -44 2 - 5 3 Go to location fifteen 4. -31 5 Go to location sixteen Go to location fourteen Transfer Task 3: Radical Race - Student Assessment Task Card 5: ( Expand and simplify 2 18 - 27 ) 2 1. 99 - 36 6 Go to location seventeen 2. 4 18 - 27 Go to location eighteen 3. 27 - 4 18 Go to location nineteen 4. 36 16 - 99 Go to location twenty Transfer Task 3: Radical Race - Student Assessment Task Card 6: When expressed in simplest form 18 2 3 1. 2 6 Go to location twenty-one 2. 6 5 Go to location twenty-two 3. 18 6 Go to location twenty-three 4. 6 6 Go to location twenty-four equals Transfer Task 3: Radical Race - Student Assessment Task Card 7: Given the equations: I. 6x + 4 - 2 = 1 II. 5 + 8x + 12 = 6 III. 15x + 10 - 3 = 1 IV. 9x + 6 + 5 = 9 V. 2x + 3 - 3 = 5 VI. 6 + 30x + 20 = 10 The four equations that have the same restrictions for x are: 1. 2. 3. 4. II, III, VI, V I, II, IV, V I, III, IV, VI II, IV, V, VI Go to location twenty-five Go to location twenty-six Go to location twenty-seven Go to location twenty-eight Transfer Task 3: Radical Race - Student Assessment Task Card 8: Determine, algebraically, the roots of the equation: 1. No solution 1 2. x = 4 1 3. x = 4 1 1 4. x = or x = 4 4 4x + 5 = 2 Go to location twenty-nine Go to location thirty Go to location thirty-one Go to location thirty-two Transfer Task 3: Radical Race - Student Assessment Task Card 9: Determine the correct combination of equations and answers from the following. P. Answers x=7 1 3x - 2 = 2 4 Q. x=4 3. 1 5x - 4 + 2 = 4 2 R. x=6 4. 25 - 3x - 5 = -3 S. No Solution ( Equations ) 1. 3 2x + 1 = -3 2. 1. 2. 3. 4. ( ) Equation 2 and answer P Equation 3 and answer Q Equation 1 and answer R Equation 4 and answer S Go to location thirty-three Go to location thirty-four Go to location thirty-five Go to location thirty-six Transfer Task 3: Radical Race - Student Assessment Task Card 10: Two squares are shown. The side length of the smaller square is 6 cm. The perimeter of the larger square in simplified form is: 1. 12 2 2. 3 2 3. 6 2 4. 24 2 Go to location thirty-seven Go to location thirty-eight Go to location thirty-nine Go to location forty Transfer Task 3: Radical Race - Student Assessment Task Card 11: Solve the equation x + 1= x 2 - 25. Explain your result. Exemplar: Location List Harry Ainlay High School Location 1: Location 12: Exit 15 Location 23: South entrance to the West Court yard Location 34: Office Entrance Location 2: Exit 2 Location 13: Exit 16 Location 24: Wellness Centre Desk Location 35: South entrance to east courtyard Location 3: Exit 5 Location 14: Exit 17 Location 25: Dance studio Entrance Location 36: Outside entrance to the Auto Location 4: Exit 4 Location 15: Outdoor class room Location 37:Inside Entrance to Construction Location 5: Exit 6 Location 16: Exit 14 Location 6: Exit 8 Location 17: Exit 13 Location 26: Cosmetology Parking Propane tank storage Location 27: North east corner of the temporary library Location 28: Southeast corner of the rotunda Location 7: Visitor Parking Stall # 116 Location 18: North East Parking lot Student Bench Location 29: Book Room 304 Location 40: Room 384 Location 8: Exit 10 Location 19: Exit 19 Location 30: Drama room Location 9: Bike Racks Location 20: Exit 20 Location 31: Theatre Entrance Location 10: Exit 11 Location 21: South entrance to student activities Location 32: Athletics Office Location 11: Exit 12 Location 22: North East corner of the Rotunda Location 33: Student Services and Career Centre Exit 1 Location 38: Inside entrance to Design Studies Location 39: Centre Table of the Rotunda Student checklist of skills: This can be done by reading out the skills and having students think about how they would rank themselves. Analysis of skills: On a scale of 1 to 10, where 1 is no confidence and 10 is you are ready to teach this concept, rank yourself on the following: Card 1: Express an entire radical as a mixed radical Card 2: Comparing and ordering radical expressions Card 3: Express a mixed radical as an entire radical. Card 4: Simplify and add or subtract radicals. Card 5: Multiply and simplify radicals. Card 6: Rationalize the denominator of a radical expression. Card 7: Determine any restrictions on values for the variable in a radical equation. Card 8: Determine algebraically, the roots of a radical equation Card 9: Verify, by substitution, that the values determined in solving a radical equation are roots of an equation. Card 10: Solve problems by modeling a situation with a radical equation and solving the equation. Card 11: Explain why some roots determined in solving a radical equation are extraneous. Radical Race - Student Assessment Task Glossary absolute value – Represents how far the number is from zero entire radical – A radical with a coefficient of 1 [Math 20-2 (Nelson: page 515)] extraneous root – A number obtained in the process of solving an equation that does not satisfy the equation mixed radicals – A radical with a coefficient other than 1 [Math 20-2 (Nelson: page 516)] perfect square – A number, from a given number system, that can be expressed as the square of a number from the same number system principal square root – The positive square root rationalize the denominator – The process used to write a radical expression that contains a radical denominator into an equivalent expression with a rational denominator [Math 20-2 (Nelson: page 517)] restrictions – The values of a the variable in an expression that ensure it to be defined [Math 20-2 (Nelson: page 517)] secondary square root – The negative square root Glossary hyperlinks redirect you to the Learn Alberta Mathematics Glossary (http://www.learnalberta.ca/content/memg/index.html). Some terms can be found in more than one division. Some terms have animations to illustrate meanings. Assessment Mathematics 20-2 Radical Race Rubric Level Criteria Excellent 3 Adequate 2 Limited 1 Performs Calculations Performs precise and explicit calculations. Performs appropriate and generally accurate calculations. Performs superficial and irrelevant calculations. Explains Choices Shows a solution for the problems; provides an insightful explanation. Shows a solution for the problem; provides explanations that are complete but vague. Shows a solution for the problem but no supporting mathematics. Glossary absolute value – Represents how far the number is from zero entire radical – A radical with a coefficient of 1 [Math 20-2 (Nelson: page 515)] extraneous root – A number obtained in the process of solving an equation that does not satisfy the equation mixed radicals – A radical with a coefficient other than 1 [Math 20-2 (Nelson: page 516)] perfect square – A number, from a given number system, that can be expressed as the square of a number from the same number system principal square root – The positive square root rationalize the denominator – The process used to write a radical expression that contains a radical denominator into an equivalent expression with a rational denominator [Math 20-2 (Nelson: page 517)] restrictions – The values of a the variable in an expression that ensure it to be defined [Math 20-2 (Nelson: page 517)] secondary square root – The negative square root Glossary hyperlinks redirect you to the Learn Alberta Mathematics Glossary (http://www.learnalberta.ca/content/memg/index.html). Some terms can be found in more than one division. Some terms have animations to illustrate meanings. Possible Solution to Radical Race Questions Cards: Master List – Answers marked with a double asterisk Card 1: Express each of the following as an entire radical. i. 2 13 ii. 3 6 iii. 4 5 iv. 5 2 1. 26, 18, 20, 10 Go to location one 2. 15, 9, 9, 9 Go to location two 3. 11, 3, 1, -3 Go to location three 4. 52, 54, 80, 50 Go to location four ** Card 2: Arrange the following in order from least to greatest i) 2 13 ii) 3 6 iii) 4 5 iv) 5 2 1. 2 13, 3 6, 4 5, 5 2 Go to location five 2. 2 13, 5 2, 3 6, 4 5 Go to location six 3. 5 2, 2 13, 3 6, 4 5 Go to location seven ** 4. 2 13, 4 5, 5 2, 3 6 Go to location eight Card 3: Convert the following mixed radicals to entire radical. iii) 2 x3 a2 a x 5 xy iv) 3xy 3 3 2z 4 i) ii) 1. 4 x 3 , a 3 , x 6 y , 3 27x 3 y 9z 4 Go to location nine 2. 4 x 3 , a 5 , x 11y , 3 27x 3 y 9z 4 Go to location ten 3. 4 x 3 , a 3 , x 11y , 3 27x 3 y 9z 4 Go to location eleven 4. 4 x 3 , a 5 , x 11y , 3 54x 3 y 9z 4 Go to location twelve ** Mathematics 20-2 Inductive and Deductive Reasoning Page 87 of 125 Card 4: Simplify the following expression by combining like radicals 3 5 1 -5 128 + 848 + 50 4 4 2 1. Go to location thirteen 2. 41 2 -36 2 - 5 3 3. -44 2 - 5 3 Go to location fifteen 4. -31 5 Go to location sixteen Go to location fourteen ** ( Card 5: Expand and simplify 2 18 - 27 ) 2 1. 99 - 36 6 Go to location seventeen ** 2. 4 18 - 27 Go to location eighteen 3. 27 - 4 18 Go to location nineteen 4. 36 16 - 99 Go to location twenty Card 6: When expressed in simplest form 18 2 equals 3 1. 2 6 Go to location twenty-one 2. 6 5 Go to location twenty-two 3. 18 6 Go to location twenty-three 4. 6 6 Go to location twenty-four ** Card 7: Given the equations: I. 6x + 4 - 2 = 1 II. 5 + 8x + 12 = 6 III. 15x + 10 - 3 = 1 IV. 9x + 6 + 5 = 9 V. 2x + 3 - 3 = 5 VI. 6 + 30x + 20 = 10 The four equations that have the same restrictions for x are: 1. 2. 3. 4. II, III, VI, V I, II, IV, V I, III, IV, VI II, IV, V, VI Mathematics 20-2 Go to location twenty-five Go to location twenty-six Go to location twenty-seven ** Go to location twenty-eight Inductive and Deductive Reasoning Page 88 of 125 Card 8: Determine, algebraically, the roots of the equation: 1. No solution 1 2. x = 4 1 3. x = 4 1 1 4. x = or x = 4 4 4x + 5 = 2 Go to location twenty-nine Go to location thirty Go to location thirty-one ** Go to location thirty-two Card 9: Determine the correct combination of equations and answers from the following. Equations Answers x=7 1. P. 3 2x + 1 = -3 ( ) 2. 1 3x - 2 = 2 4 Q. x=4 3. 1 5x - 4 + 2 = 4 2 R. x=6 4. 25 - 3x - 5 = -3 S. No Solution 1. 2. 3. 4. ( ) Equation 2 and answer P Equation 3 and answer Q Equation 1 and answer R Equation 4 and answer S Go to location thirty-three Go to location thirty-four ** Go to location thirty-five Go to location thirty-six Card 10: Two squares are shown. The side length of the smaller square is 6 cm. The perimeter of the larger square in simplified form is: 1. 12 2 Go to location thirty-seven 2. 3 2 Go to location thirty-eight 3. 6 2 Go to location thirty-nine 4. 24 2 Go to location forty ** Card 11: Solve the equation x + 1= x 2 - 25. Explain your result. x 2 + 2x + 1 = x 2 - 25 x = -13 ( ) Check: -13 + 1 = ( -13) 2 - 25 - 12 = 12 No Solution Mathematics 20-2 Inductive and Deductive Reasoning Page 89 of 125 STAGE 3 Learning Plans Lesson 1 What Should I Remember? STAGE 1 BIG IDEA: Understanding radicals will further develop student’s sense of exact values, and enhance their ability to simplify expressions and solve equations. ENDURING UNDERSTANDINGS: Students will understand … There are appropriate forms of communications in mathematics. Radicals are more precise efficient, concise and accurate. ESSENTIAL QUESTIONS: Under what circumstances would a mixed radical or an entire radical be appropriate? When is x > y? KNOWLEDGE: SKILLS: Students will know … Students will be able to … when the expression is simplified simplify radical expressions with numerical or variable radicands 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 Inductive and Deductive Reasoning Page 90 of 125 Lesson Summary This lesson will review prior knowledge needed in this unit. Definitions of square roots, cube roots, perfect squares, perfect cubes and radicals Estimate radicals Compare and order numbers Mixed to entire radicals Entire to mixed radicals Review operations on polynomials so as to connect those with operations on radicals Lesson Plan Hook What do you see? (Think Pair Share) 3 25 5 5 27 3 3 Have a Think-Pair-Share discussion involving the picture above in relation to square roots, cube roots, perfect squares, perfect cubes, factors, etc. After the Think-Pair-Share ask students to define the following o Square Root o Cube Root o Perfect Square (List as many as you can) o Perfect Cube (List as many as you can) Lesson Goal Activate prior knowledge Mathematics 20-2 Inductive and Deductive Reasoning Page 91 of 125 Lesson Sorting Activity Create groups and handout a number card from the same set to each member of the group. The group must sort themselves from lowest to highest. Each member should try to determine the approximate value of his or her card. Not allowing a calculator will help students refine their number sense. Possible sets of numbers 3 o 2, 1.9, 3 9, 8, o 5, 2 3, 3.9, 2 7, 3 5, 6, 51 o 2 3 2, 3 27, 2 3 4, 3 27, 4.9, 26 64, 4.1, 3 3 3, 5 L1 Sorting Activity (3 sets of numbers) files were added to Appendix files were added to the EPSB Understanding by Design share site Entire to Mixed / Mixed to Entire Puzzle Activity Groups of students receive the puzzle in pieces and perhaps a blank nine by nine grid. A math joke is presented to them “What does the little mermaid wear?” and they have to assemble the puzzle correctly by lining up the entire radical side with its corresponding mixed radical side. The letters on the puzzle make up the answer (the answer is “an algae-bra”). NOTE: the orientation of the letters has been scrambled to avoid giving directional clues. L1 Puzzle Activity file was added to Appendix file was added to the EPSB Understanding by Design share site Going Beyond Resources Math 20-2 (Nelson: sec 4.1, page(s) 176-183) Supporting Mathematics 20-2 Inductive and Deductive Reasoning Page 92 of 125 Assessment Glossary entire radical – A radical with a coefficient of 1 [Math 20-2 (Nelson: page 515)] mixed radicals – A radical with a coefficient other than 1 [Math 20-2 (Nelson: page 516)] perfect square – A number, from a given number system, that can be expressed as the square of a number from the same number system perfect cube – A number, from a given number system, that can be expressed as the cube of a number from the same number system. Glossary hyperlinks redirect you to the Learn Alberta Mathematics Glossary (http://www.learnalberta.ca/content/memg/index.html). Some terms can be found in more than one division. Some terms have animations to illustrate meanings. Other Mathematics 20-2 Inductive and Deductive Reasoning Page 93 of 125 Lesson 2 What’s with all the Letters? STAGE 1 BIG IDEA: Understanding radicals will further develop student’s sense of exact values, and enhance their ability to simplify expressions and solve equations. ENDURING UNDERSTANDINGS: Students will understand … There are restrictions on values for the variable in a radical. There are appropriate forms of communications in mathematics. ESSENTIAL QUESTIONS: Why is there a restriction on the domain? Why does your calculator say ERROR on Under what circumstances would a mixed radical or an entire radical be appropriate? -2 ? KNOWLEDGE: SKILLS: Students will know … Students will be able to … the square root of a negative is not a real number when the expression is simplified Mathematics 20-2 identify values of the variable for which the radical expression is defined simplify radical expressions with numerical or variable radicands Inductive and Deductive Reasoning Page 94 of 125 Lesson Summary Warm Up Activity Development Binomial Radicands Restriction Entire to Mixed Radicals with Variables Mixed to Entire Radicals with Variables Lesson Plan Warm Up Activity Option A: Determine two identical numbers that will give these products. 1 25 16 100, 49, 225, 0, - 36, - 16, , 54, , - , 1.21, 27.04 4 9 49 Discuss what the restrictions would be in the value(s) of: 1. the product 2. the identical numbers Option B: Sort these numbers according to some sort of criteria (can be done individually or in groups) 16 , 325, 1.44, 0, 81 Ask students how they sorted these values. 100, 38, -36, 49, - 25 , 9.61 9 Questions to ask: 1. Are there answers for all of these? (Discuss what’s defined.) 2. Are there any interesting unexpected answers? Option C: Have students generate a list of square roots where the radicand is positive or negative, then evaluate these. Questions to ask: 1. Are there answers for all of these? (Discuss what’s defined.) 2. Are there any interesting unexpected answers? To meet curricular objectives consider repeating using cubic roots for all options. The intent of the warm-up would be for students to discover the restriction on square roots (which doesn’t apply to cubic roots) is that the radicand must be greater than or equal to zero. This should be summarized and recorded in some way. To enhance the understanding of restrictions students should also see radicals of the form Mathematics 20-2 Inductive and Deductive Reasoning ax + b. Page 95 of 125 DI Suggestions Consider an extension to roots beyond cubic, looking for patterns between odd an even indexed roots Consider a graphing activity designed to explore the domain of square and cubic roots Development Present students with the following list and ask them to identify the perfect squares: x , x 2, x 3 , x 4, x 5, x 6 Using this knowledge try simplifying the following list: x , x 2, x 3, x 4, x 5, x 6 Note that the accurate simplification for x 3 would be x x ,but we will always assume the principal root for the purposes of this course and will instead simplify x 3 to x x . It would be beneficial for students to be introduced to numerical coefficients combined with variable radicands before having students practice this concept. For example, 2 18x 5 can be rewritten as 6x 2 2x . An optional activity would be to have students take mixed radicals (with variable in the coefficients) and convert these to entire radicals (ie working backwards from previous method). However, there are no questions provided in this resource. Sorting Activity Provide students with a list of numbers and ask them to sort them according to criteria of their choice. Guide them toward selecting defined and undefined. Start with a list of positive and negative square roots. (Include 0) Next make a list of positive and negative cube roots (Include 0). DI Suggestion Make a list of positive and negative even and odd indexed roots. DI Graphing Activities Graph basic square root and cube root functions to analyze the domain. Extension: Have students plot the given numbers (x is radicand and y is square root of radicand). Mathematics 20-2 Inductive and Deductive Reasoning Page 96 of 125 Binomial Radicands Restriction Once students understand the basic restrictions on x, extend it to binomials. This was previously mentioned in Warm Up Activity, Option C. Entire to Mixed Radicals with Variables Start with a list to see a pattern. x , x 2, x 3 , x 4 , ... and then practice. L2 Converting Entire to Mixed Worksheet file was added to Appendix file was added to the EPSB Understanding by Design share site Mixed to Entire Radicals with Variables Compare to the numerical strategy and practice. L2 Converting Mixed to Entire Worksheet file was added to Appendix file was added to the EPSB Understanding by Design share site Going Beyond Resources Math 20-2 (Nelson, page 211, #1, 2, 3, 11) Worksheet Supporting Assessment Mathematics 20-2 Inductive and Deductive Reasoning Page 97 of 125 Glossary entire radical – A radical with a coefficient of 1 [Math 20-2 (Nelson: page 515)] mixed radicals – A radical with a coefficient other than 1 [Math 20-2 (Nelson: page 516)] restrictions – The values of a the variable in an expression that ensure it to be defined [Math 20-2 (Nelson: page 517)] Glossary hyperlinks redirect you to the Learn Alberta Mathematics Glossary (http://www.learnalberta.ca/content/memg/index.html). Some terms can be found in more than one division. Some terms have animations to illustrate meanings. Other Mathematics 20-2 Inductive and Deductive Reasoning Page 98 of 125 Lesson 3 Let’s Play Operation (Operations on Radicals) STAGE 1 BIG IDEA: Understanding radicals will further develop student’s sense of exact values, and enhance their ability to simplify expressions and solve equations. ENDURING UNDERSTANDINGS: ESSENTIAL QUESTIONS: Students will understand … There are restrictions on values for the variable in a radical. There are appropriate forms of communications in mathematics. Radicals are more precise efficient, concise and accurate. Operations can be performed on radicals, as with other numbers or expressions. When is an exact solution required? Under what circumstances would a mixed radical or an entire radical be appropriate? When would you use radicals? KNOWLEDGE: SKILLS: Students will know … Students will be able to … when the expression is simplified what like terms are the rules for operations on radicals Mathematics 20-2 identify values of the variable for which the radical expression is defined simplify radical expressions with numerical or variable radicands rationalize the monomial denominator of a radical expression perform operations with radicals Inductive and Deductive Reasoning Page 99 of 125 Lesson Summary Students will explore and practice the operations on radicals. Lesson Plan Add / Subtract Radicals Adding and Subtracting Radicals Discovery Activity This activity will ask students to discover and practice the rules for adding and subtracting radicals. The false examples may be used to discuss common errors. Challenge questions extend concept to include variables and more complex questions. L3 Adding and Subtracting Radicals Discovery Activity file was added to Appendix file was added to the EPSB Understanding by Design share site L3 Adding and Subtracting Radicals Key PDF file was added to the EPSB Understanding by Design share site Visual Representation A visual representation may be used to reinforce the concept of adding and subtracting like radicals. There is a file with examples of the visualization in use (Example Add Subtract Visual) and then a file to be used to solve additional questions (Interactive Add Subtract Visual). L3 Visual Representation notebook files were added to the EPSB Understanding by Design share site Reinforce concepts with practice from textbook. Multiplying Radicals Multiplying Radicals Discovery Activity This activity will ask students to discover and practice the rules for multiplying radicals. The false examples may be used to discuss common errors. Challenge questions extend concept to include variables and more complex questions. Mathematics 20-2 Inductive and Deductive Reasoning Page 100 of 125 L3 Multiplying Radicals Discovery Activity file was added to Appendix file was added to the EPSB Understanding by Design share site L3 Multiplying Radicals Key PDF file was added to the EPSB Understanding by Design share site Reinforce concepts with practice from textbook. Dividing Radicals Dividing Radicals Introduction Warm Up o Review squaring radicals and equivalent fractions. Define and Discuss Rationalizing o Reasons for rationalizing include consistency, communication, and comparisons. Examples: Division & Rationalizing o Discuss various strategies to solve the problem (division, simplifying, or rationalize first) o Nelson Principles of Mathematics 11 has an excellent example of multiple strategies on pages 194-196. Reinforce concepts with practice from textbook. L3 Dividing Radicals Introduction file was added to Appendix file was added to the EPSB Understanding by Design share site L3 Dividing Radicals Key PDF file was added to the EPSB Understanding by Design share site Remember: when dealing with expressions with variables you should state the restrictions on the variable. Explain a Process Assignment This type of assignment may be used for each operation on radicals. The assignment simply involves students writing an explanation of how to do the operation and providing an example of a solution. This assignment may reinforce/assess understanding while working on communication skills. Mathematics 20-2 Inductive and Deductive Reasoning Page 101 of 125 Going Beyond Resources Math 20-2 (Nelson: sec 4.3, page(s) 184-190) Math 20-2 (Nelson: sec 4.3, page(s) 191-201) Assessment Glossary absolute value – Represents how far the number is from zero entire radical – A radical with a coefficient of 1 [Math 20-2 (Nelson: page 515)] extraneous root – A number obtained in the process of solving an equation that does not satisfy the equation mixed radicals – A radical with a coefficient other than 1 [Math 20-2 (Nelson: page 516)] perfect square – A number, from a given number system, that can be expressed as the square of a number from the same number system principal square root – The positive square root rationalize the denominator – The process used to write a radical expression that contains a radical denominator into an equivalent expression with a rational denominator [Math 20-2 (Nelson: page 517)] restrictions – The values of a the variable in an expression that ensure it to be defined [Math 20-2 (Nelson: page 517)] secondary square root – The negative square root Other Mathematics 20-2 Inductive and Deductive Reasoning Page 102 of 125 Lesson 4 Radical Issues (Solving Radical Equations) STAGE 1 BIG IDEA: Understanding radicals will further develop student’s sense of exact values, and enhance their ability to simplify expressions and solve equations. ENDURING UNDERSTANDINGS: ESSENTIAL QUESTIONS: Students will understand … There are restrictions on values for the variable in a radical. Some equations have extraneous roots, and why. There are appropriate forms of communications in mathematics. Radicals are more precise efficient, concise and accurate. Operations can be performed on radicals, as with other numbers or expressions. Why are extraneous roots produced? Why is there a restriction on the domain? Why does your calculator say ERROR on When is an exact solution required? Under what circumstances would a mixed radical or an entire radical be appropriate? When would you use radicals? -2 ? KNOWLEDGE: SKILLS: Students will know … Students will be able to … the square root of a negative is not a real number all roots determined algebraically need to be verified when it is appropriate to use an exact value versus a rounded decimal what like terms are the rules for operations on radicals Mathematics 20-2 determine any restrictions on values for the variable in a radical equation verify, by substitution, that the values determined in solving a radical equation are roots of the equation model a situation with a radical equation solve radical equations to determine the roots Inductive and Deductive Reasoning Page 103 of 125 Lesson Summary Use a table with appropriate data to introduce a cubic root function. Explore methods to solve radical functions. Lesson Plan Provide students with the following data table. Have students look for a pattern, to make it easier for them you may want to inform them that it’s a cubic root function. x 5 24 61 132 213 y 4 6 8 10 12 For students that are struggling you may want to inform that the function is of the form y =a3 x +b Solution: y = 23 x + 3 Discuss the solution with respect to the domain of x. Are there any restrictions? Here is a link to some application questions that could be used as examples or have students work through together in an attempt to understand the solving process. http://cnx.org/content/m21965/latest/ One example from the site: Mathematics 20-2 Inductive and Deductive Reasoning Page 104 of 125 Answers: (a) 7.96 (b) 5 Other problems that could be searched: Using the distance formula Meteorology problems: length of time vs. diameter of storm Length of diagonal in a cube Given an expression representing the volume of a 3D object, calculate the surface area (or vice versa) Numerous problems from Physics texts. (Questions involving periods, kinetic energy, etc) Discussion during the problem solving process should involve extraneous roots. To assist in the discussion students must know how to verify their answers. From here contrast between exact values vs. approximate value answers. Example: Calculate the side length of a cube that has a volume of 375 cm 3. From there calculate the surface area of the cube. Approximate Solution: r = 375 3 = 7.2 ( ) SA = 6 7.2 Exact Solution: r = 3 375 = 3 125 ´ 3 3 = 53 3 2 = 311 cm2 ( ) cm = 150 ( 9 ) cm SA = 6 5 3 3 2 3 2 2 = 312 cm2 Using this value for volume it is interesting to note that the answers differ by 1 cm 2. It may be worthwhile having a discussion whether or not this is significant. What if the volume was greater? Mathematics 20-2 Inductive and Deductive Reasoning Page 105 of 125 The remainder of the lesson should be spent on rearranging radical equations to isolate the unknown. The focus should be on performing opposite operations. A comparison to equations solved in previous years is suggested. Linear 3x = 9 divide both sides by 3 x=3 3(x + 2) = 9 Divide both sides by 3 x+2=3 Subtract both sides by 2 x=1 3(x + 2) – 6 = 9 Add both sides by 6 3(x + 2) = 15 Divide both sides by 3 x+2=5 Subtract both sides by 2 x=3 Radical x = 25 Square both sides x = 625 x + 2 = 25 Square both sides x + 2 = 625 Subtract both sides by 2 x = 623 x + 2 - 6 = 19 Add both sides by 6 x + 2 = 25 Square both sides x + 2 = 625 Subtract both sides by 2 x = 623 After guiding students through a few of these it would be beneficial to present students with a more complicated equation to work on individually or in groups. For example, 8 = 3 2x - 25 -13 x = 37 In order to assist in the transfer task students should be exposed to equations that are not limited to variable as radicands only. For example 3 + x -1 = x Going Beyond Resources Math 20-2 (Nelson, page 222, #1-17) Mathematics 20-2 Inductive and Deductive Reasoning Page 106 of 125 Supporting Assessment Glossary absolute value – Represents how far the number is from zero entire radical – A radical with a coefficient of 1 [Math 20-2 (Nelson: page 515)] extraneous root – A number obtained in the process of solving an equation that does not satisfy the equation mixed radicals – A radical with a coefficient other than 1 [Math 20-2 (Nelson: page 516)] perfect square – A number, from a given number system, that can be expressed as the square of a number from the same number system principal square root – The positive square root rationalize the denominator – The process used to write a radical expression that contains a radical denominator into an equivalent expression with a rational denominator [Math 20-2 (Nelson: page 517)] restrictions – The values of a the variable in an expression that ensure it to be defined [Math 20-2 (Nelson: page 517)] secondary square root – The negative r square root Glossary hyperlinks redirect you to the Learn Alberta Mathematics Glossary (http://www.learnalberta.ca/content/memg/index.html). Some terms can be found in more than one division. Some terms have animations to illustrate meanings. Other Mathematics 20-2 Inductive and Deductive Reasoning Page 107 of 125 Appendix Copies of worksheets for Lessons 1 – 3 follow: Lesson 1 Radicals Sorting Number Set 1 Lesson 1 Radicals Sorting Number Set 2 Lesson 1 Radicals Sorting Number Set 3 Lesson 1 Mixed to Entire Puzzle Activity & Answers Lesson 2 Converting Entire to Mixed & Answers Lesson 2 Converting Mixed to Entire Radical Worksheet & Answers Lesson 3 Adding and Subtracting Radicals & Answers Lesson 3 Multiplying Radicals & Answers Lesson 3 Dividing Radicals Introduction & Answers Lesson 3 Converting Mixed to Entire Radical Worksheet & Answers Mathematics 20-2 Inductive and Deductive Reasoning Page 108 of 125 M20-2 Lesson 1 Radicals Sorting Number Set 1 2 1.9 3 8 3 4.9 27 26 Mathematics 20-2 Inductive and Deductive Reasoning Page 109 of 125 9 M20-2 Lesson 1 Radicals Sorting Number Set 2 5 2 3 3.9 6 2 7 3 5 51 Mathematics 20-2 Inductive and Deductive Reasoning Page 110 of 125 M20-2 Lesson 1 Radicals Sorting Number Set 3 3 2 3 3 64 3 3 27 2 4 4.1 5 Mathematics 20-2 Inductive and Deductive Reasoning Page 111 of 125 3 3 3 M20-2 Lesson 1 Mixed to Entire Puzzle Activity Preparation: copy and cut along the gridlines. Mathematics 20-2 Inductive and Deductive Reasoning Page 112 of 125 M20-2 Lesson 1 Mixed to Entire Puzzle Activity – Student Answers What does the little mermaid wear?” Answer: AN ALGAE-BRA Mathematics 20-2 Inductive and Deductive Reasoning Page 113 of 125 M20-2 Lesson 2 Converting Entire to Mixed Worksheet (Variable Radicands) Simplify the following. 1. √𝑥 8 2. √49𝑥 2 3. √125𝑥 4 3 9. √−1000𝑥 3 3 27 10. √64 𝑥 6 3 11. √−125𝑥 8 4. √48𝑥 5 3 12. √363𝑥16 9 5. √4 𝑥10 6. √1.69𝑥 3 3 1 13. √8 𝑥12 3 14. √0.125𝑥 9 64 7. √ 9 𝑥 7 8. √4.41𝑥 9 3 15. 2√216𝑥 5 3 8 16. 10√125 𝑥 7 Extra Problem 3 √−3375𝑥 −12 𝑦 21 Mathematics 20-2 Inductive and Deductive Reasoning Page 114 of 125 Answers: 1. 2. 3. 4. 5. 𝑥4 7𝑥 5𝑥 2 √5 4𝑥 2 √𝑥 3 5 𝑥 2 6. 1.3𝑥√𝑥 8 7. 3 𝑥 3 √𝑥 8. 2.1𝑥 4 √𝑥 9. −10𝑥 3 10. 4 𝑥 2 11. 12. 13. 14. 15. 16. 3 −5𝑥 2 √𝑥 2 3 11𝑥 5 √3𝑥 1 4 𝑥 2 0.5𝑥 3 3 12𝑥 √𝑥 2 3 4𝑥 2 √𝑥 Extra Problem −15𝑥 −4 𝑦 7 Mathematics 20-2 Inductive and Deductive Reasoning Page 115 of 125 M20-2 Lesson 2 Converting Mixed to Entire Radical Worksheet 1. 3𝑥√2𝑥 2. 3 𝑥 2 √𝑥 4 3. 5𝑥 3 √3 4. 1 3 𝑦 3 √2 𝑦 2 3 6. 2𝑥 ∙ √𝑥 2 7. 1 3 3 𝑥 2 ∙ √2𝑥 3 8. 1.2𝑥 ∙ √5 9. 2𝑦 ∙ 3√125𝑦 2 5. 5.1𝑦√7𝑦 10. 3.4𝑦 3 ∙ √5 Extra Problem 2 3 2 3 3 2 𝑥 𝑦 ∙ √ 𝑥𝑦 3 2 Mathematics 20-2 Inductive and Deductive Reasoning Page 116 of 125 Answers: 1. √18𝑥 3 9 2. √16 𝑥 5 3. √75𝑥 6 3 4. √8 𝑦 7 5. √182.07𝑦 3 3 6. √8𝑥 5 3 2 7. √27 𝑥 7 3 8. √8.64𝑥 3 3 9. √1000𝑦 4 578 10. √4.624𝑦 6 OR √128 𝑦 6 Extra Problem 4 √ 𝑥10 𝑦 3 9 3 Mathematics 20-2 Inductive and Deductive Reasoning Page 117 of 125 M20-2 Lesson 3 Adding and Subtracting Radicals Discovery Activity If these are true …………………………………………………………………… and these are false. 3 5 6 5 9 5 3 5 6 5 9 10 8 7 3 7 5 7 8 7 3 7 5 0 13 5 13 6 13 13 5 13 5 13 8 +3 2 =5 2 8 3 2 4 10 27 12 9 3 4 3 27 12 5 3 13 3 then find the answer to these: 20 13 10 13 4 11 11 8 18 2 12 48 (Hint: Think about addition & subtraction of polynomials.) … and now see if you can do these! 7 5 3 3 27 5 12 75 4 x 3 x 5 x 3 x3 x x 3 Mathematics 20-2 Inductive and Deductive Reasoning Page 118 of 125 Answers: Mathematics 20-2 Inductive and Deductive Reasoning Page 119 of 125 M20-2 Lesson 3 Multiplying Radicals Discovery Activity If these are true …………………………………………………………………… and these are false. 3 7 ( 3)( 7) = 21 3 2 4 5 12 5 5 3 2 4 5 7 10 5 5 25 5 3 3 3 2 2 6 2 10 10 25 5 3 3 9 2 2 6 2 12 4 3 12 24 then find the answer to these: 2 11 3 5 2 2 8 8 5 6 3 3 (Hint: Think about addition & subtraction of polynomials.) … and now see if you can do these! 2 x 5 x 4 x 7 x3 Mathematics 20-2 x 2x 3 5 x 4 2 3 3 7 8 8 Inductive and Deductive Reasoning Page 120 of 125 Answers: Mathematics 20-2 Inductive and Deductive Reasoning Page 121 of 125 M20-2 Lesson 3 Dividing Radicals Introduction Warm Up Solve the following: Write three equivalent fractions for each of the following: 2 2 _______ 3 3 _______ 4 4 _______ 5 5 _______ 2 3 6 12 Rationalizing What is rationalizing? Why do we rationalize? Examples a) c) 5 2 6 3 b) d) 6 7x 5 3x 2 10 4 2 and now… 3 12 7 6 3 3 5 9 24 x 5 Mathematics 20-2 3 x Inductive and Deductive Reasoning Page 122 of 125 Answers: Mathematics 20-2 Inductive and Deductive Reasoning Page 123 of 125 M20-2 Lesson 3 Converting Mixed to Entire Radical Worksheet 11. 3𝑥√2𝑥 3 3 16. 2𝑥 ∙ √𝑥 2 1 3 12. 4 𝑥 2 √𝑥 17. 3 𝑥 2 ∙ √2𝑥 13. 5𝑥 3 √3 18. 1.2𝑥 ∙ √5 1 3 14. 2 𝑦 3 √2 𝑦 3 19. 2𝑦 ∙ 3√125𝑦 2 15. 5.1𝑦√7𝑦 20. 3.4𝑦 3 ∙ √5 Extra Problem 2 3 2 3 3 2 𝑥 𝑦 ∙ √ 𝑥𝑦 3 2 Mathematics 20-2 Inductive and Deductive Reasoning Page 124 of 125 Answers: 11. √18𝑥 3 9 12. √16 𝑥 5 13. √75𝑥 6 3 14. √8 𝑦 7 15. √182.07𝑦 3 3 16. √8𝑥 5 3 2 17. √27 𝑥 7 3 18. √8.64𝑥 3 3 19. √1000𝑦 4 578 20. √4.624𝑦 6 OR √128 𝑦 6 Extra Problem 4 √ 𝑥10 𝑦 3 9 3 Mathematics 20-2 Inductive and Deductive Reasoning Page 125 of 125