New York State Common Core Mathematics Curriculum PRECALCULUS • MODULE 1
Table of Contents1 Complex Numbers and Transformations Module Overview .................................................................................................................................................. 3 Topic A: A Question of Linearity (N‐CN.3, N‐CN.4) ................................................................................................. x Lesson 1‐2: Wishful Thinking—Does Linearity Hold? ............................................................................... x Lesson 3: Which Real‐Number Functions Define a Linear Transformation? ............................................. x Lesson 4‐5: An Appearance of Complex Numbers .................................................................................... x Lesson 6‐7: Complex Number Division ...................................................................................................... x Topic B: Complex Number Operations as Transformations (N‐CN.3, N‐CN.4, N‐CN.5, N‐CN.6, G‐CO.2, G‐CO.4, G‐CO.5) ........................................................................................................................................ x Lesson 8‐9: The Geometric Effect of Some Complex Arithmetic .............................................................. x Lesson 10‐11: Distance and Complex Numbers ........................................................................................ x Lesson 12: Trigonometry and Complex Numbers ..................................................................................... x Lesson 13‐15: Modeling Mathematics Itself—Discovering the Geometric Effect of Complex Multiplication ...................................................................................................... x Lesson 16: The Geometric Effect of Multiplying by a Reciprocal .............................................................. x Mid‐Module Assessment and Rubric .................................................................................................................... 9 Topics A through B (assessment 1 day, return 1 day, remediation or further applications 3 days) Topic C: The Power of the Right Notation (N‐CN.4, N‐CN.5, N‐VM.10, N‐VM.11, N‐VM.12, G‐CO.2, G‐CO.4, G‐CO.5) ........................................................................................................................................ x Lesson 17‐19: Exploiting the Connection to Trigonometry ....................................................................... x Lesson 20: Exploiting the Connection to Cartesian Coordinates ............................................................... x Lesson 21: The Hunt for Better Notation .................................................................................................. x Lesson 22‐23: Modeling Video‐Game Motion with Matrices ................................................................... x Lesson 24‐25: Matrix Notation Encompasses New Transformations! ...................................................... x Lesson 26‐27: Getting a Handle on New Transformations ........................................................................ x Lesson 28‐30: When Can We Reverse a Transformation? ........................................................................ x 1
Each lesson is ONE day and ONE day is considered a 45 minute period. Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
Module Overview
M1
PRECALCULUS End‐of‐Module Assessment and Rubric .............................................................................................................. 22 Topics A through C (assessment 1 day, return 1 day, remediation or further applications 3 days)
Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
Module Overview
M1
PRECALCULUS Precalculus • Module 1 Complex Numbers and Transformations OVERVIEW Module 1 sets the stage for expanding students’ understanding of transformations by first exploring the notion of linearity in an algebraic context (“Which familiar algebraic functions are linear?”). This quickly leads to a return to the study of complex numbers and a study of linear transformations in the complex plane. Thus, Module 1 builds on standards N‐CN.1 and N‐CN.2, introduced in Grade 11, and standards G‐CO.2, G‐
CO.4, and G‐CO.5, introduced in Grade 10. In Topic A, students examine this story of linearity which leads to the reappearance of complex numbers. In Topic B, students come to understand that complex number multiplication has the geometric effect of a rotation followed by dilation in the complex plane. They learn that the algebraic inverse of a complex number (i.e., its reciprocal) provides the inverse geometric operation. Analysis of the angle of rotation and the scale of the dilation brings a return to topics in trigonometry first introduced in Grade 10 (G‐SRT.6, G‐SRT.7, G‐
SRT.8) and expanded on in Grade 11 (F‐TF.1, F‐TF.2, F‐TF.8). It also introduces the notion of the modulus and the argument of a complex number. The theme of Topic C is to highlight the effect of the changing perspective regarding complex numbers and to make full use of the notation implied by that change of perspective. By exploiting the connection to trigonometry students see how much of complex arithmetic is simplified. By regarding complex numbers as points in the Cartesian plane (a concept developed since Grade 9) we can begin to write analytic formulas for translations, rotations and dilations in the plane, and revisit the ideas of Grade 10 geometry (G‐CO.2, G‐CO.4, G‐CO.5) in this light. Taking this work one step further, students develop the 2 x 2 matrix notation for planar transformations. This work sheds light on how geometry software and video games efficiently perform rigid motion calculations. Finally, the flexibility implied by 2 x 2 matrix notation allows students to study additional matrix transformations that do not necessarily arise from our original complex‐number thinking context. The Mid‐Module Assessment follows Topic B. The End‐of‐Module Assessment follows Topic C. Focus Standards Perform arithmetic operations with complex numbers. N‐CN.3 (+) Find the conjugate of a complex number; use conjugates to find moduli and quotients of complex numbers. Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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Module Overview
M1
PRECALCULUS Represent complex numbers and their operations on the complex plane. N‐CN.4 (+) Represent complex numbers on the complex plane in rectangular and polar form (including real and imaginary numbers), and explain why the rectangular and polar forms of a given complex number represent the same number. N‐CN.5 (+) Represent addition, subtraction, multiplication, and conjugation of complex numbers geometrically on the complex plane; use properties of this representation for computation. For example, (–1 + √3 i)3 = 8 because (–1 + √3 i) has modulus 2 and argument 120°. N‐CN.6 (+) Calculate the distance between numbers in the complex plane as the modulus of the difference, and the midpoint of a segment as the average of the numbers at its endpoints. Perform operations on matrices and use matrices in applications. N‐VM.10 (+) Understand that the zero and identity matrices play a role in matrix addition and multiplication similar to the role of 0 and 1 in the real numbers. The determinant of a square matrix is nonzero if and only if the matrix has a multiplicative inverse. N‐VM.11 (+) Multiply a vector (regarded as a matrix with one column) by a matrix of suitable dimensions to produce another vector. Work with matrices as transformations of vectors. N‐VM.12 (+) Work with 2 x 2 matrices as transformations of the plane, and interpret the absolute value of the determinant in terms of area. Experiment with transformations in the plane. G‐CO.2 Represent transformations in the plane using, e.g., transparencies and geometry software; describe transformations as functions that take points in the plane as inputs and give other points as outputs. Compare transformations that preserve distance and angle to those that do not (e.g., translation versus horizontal stretch). G‐CO.4 Develop definitions of rotations, reflections, and translations in terms of angles, circles, perpendicular lines, parallel lines, and line segments. G‐CO.5 Given a geometric figure and a rotation, reflection, or translation, draw the transformed figure using, e.g., graph paper, tracing paper, or geometry software. Specify a sequence of transformations that will carry a given figure onto another. Foundational Standards Reason quantitatively and use units to solve problems. N‐Q.2 ★
Define appropriate quantities for the purpose of descriptive modeling. Perform arithmetic operations with complex numbers. N‐CN.1 Know there is a complex number i such that i2 = –1, and every complex number has the form a + bi with a and b real. Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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N‐CN.2 Module Overview
M1
PRECALCULUS Use the relation i2 = –1 and the commutative, associative, and distributive properties to add, subtract, and multiply complex numbers. Use complex numbers in polynomial identities and equations. N‐CN.7 Solve quadratic equations with real coefficients that have complex solutions. N‐CN.8 (+) Extend polynomial identities to the complex numbers. For example, rewrite x2 + 4 as (x + 2i)(x – 2i). Interpret the structure of expressions. A‐SSE.1 ★
Interpret expressions that represent a quantity in terms of its context. a.
Interpret parts of an expression, such as terms, factors, and coefficients. b.
Interpret complicated expressions by viewing one or more of their parts as a single entity. For example, interpret P(1+r)n as the product of P and a factor not depending on P. Write expressions in equivalent forms to solve problems. A‐SSE.3 Choose and produce an equivalent form of an expression to reveal and explain properties of ★
the quantity represented by the expression. a. Factor a quadratic expression to reveal the zeros of the function it defines. b. Complete the square in a quadratic expression to reveal the maximum or minimum value of the function it defines. c. Use the properties of exponents to transform expressions for exponential functions. For example, the expression 1.15t can be rewritten as (1.151/12)12t ≈ 1.01212t to reveal the approximate equivalent monthly interest rate if the annual rate is 15%. Create equations that describe numbers or relationships. A‐CED.1 Create equations and inequalities in one variable and use them to solve problems. Include equations arising from linear and quadratic functions, and simple rational and exponential functions. A‐CED.2 Create equations in two or more variables to represent relationships between quantities; graph equations on coordinate axes with labels and scales. A‐CED.3 Represent constraints by equations or inequalities, and by systems of equations and/or inequalities, and interpret solutions as viable or nonviable options in a modeling context. For example, represent inequalities describing nutritional and cost constraints on combinations of different foods. A‐CED.4 Rearrange formulas to highlight a quantity of interest, using the same reasoning as in solving equations. For example, rearrange Ohm’s law V = IR to highlight resistance R. Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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Module Overview
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PRECALCULUS Understand solving equations as a process of reasoning and explain the reasoning. A‐REI.1 Explain each step in solving a simple equation as following from the equality of numbers asserted at the previous step, starting from the assumption that the original equation has a solution. Construct a viable argument to justify a solution method. Solve equations and inequalities in one variable. A‐REI.3 Solve linear equations and inequalities in one variable, including equations with coefficients represented by letters. A‐REI.6 Solve systems of linear equations exactly and approximately (e.g., with graphs), focusing on pairs of linear equations in two variables. Extend the domain of trigonometric functions using the unit circle. F‐TF.1 Understand radian measure of an angle as the length of the arc on the unit circle subtended by the angle. F‐TF.2 Explain how the unit circle in the coordinate plane enables the extension of trigonometric functions to all real numbers, interpreted as radian measures of angles traversed counterclockwise around the unit circle. F‐TF.3 (+) Use special triangles to determine geometrically the values of sine, cosine, tangent for π/3, π/4 and π/6, and use the unit circle to express the values of sine, cosine, and tangent for π–x, π+x, and 2π–x in terms of their values for x, where x is any real number. Prove and apply trigonometric identities. F‐TF.8 Prove the Pythagorean identity sin2(θ) + cos2(θ) = 1 and use it to find sin(θ), cos(θ), or tan(θ) given sin(θ), cos(θ), or tan(θ) and the quadrant of the angle. Focus Standards for Mathematical Practice MP.1 Make sense of problems and persevere in solving them. Students learn when ideal linearity properties do and do not hold for classes of functions. MP.2 Reason abstractly and quantitatively. Students develop the understanding that multiplication by a complex number corresponds to the geometric action of a rotation and dilation from the origin in the complex plane. Students apply this knowledge to understand that multiplication by the reciprocal provides the inverse geometric operation to a rotation and dilation. MP.3 Construct viable arguments and critique the reasoning of others. Students study examples of common mistakes by algebra students and decide when purported algebraic identities do or do not hold, and then develop the correct general algebraic results. Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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Module Overview
M1
PRECALCULUS MP.4 Model with mathematics. Students discover the geometric effect of complex multiplication and use it to model computer animation in the plane by rotating and translating through matrix operations and equivalent addition of 2 x 1 vectors. MP.7 Look for and make use of structure. Students utilize the rectangular representation, complex numbers, to interpret certain planar transformations as operations in complex arithmetic. Students understand that the absolute value of the determinant of a 2 x 2 matrix is the area of the image of the unit square and that an inverse transformation, when represented by a 2 x 2 matrix, exists precisely when the determinant of that matrix is non‐zero. MP.8 Look for and express regularity in repeated reasoning. Students extend linearity conditions to functions with complex values and develop complex number arithmetic in this context. Terminology New or Recently Introduced Terms 






Linear Transformation Conjugate Modulus Argument Polar Form Matrix Determinant Familiar Terms and Symbols2 





Complex Number Rotation Dilation Translation Rectangular Coordinates Trigonometry 2
These are terms and symbols students have seen previously. Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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Module Overview
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PRECALCULUS Suggested Tools and Representations 


Graphing Calculator Wolfram Alpha Software Geometer’s Sketchpad Software Assessment Summary Assessment Type Administered Mid‐Module Assessment Task End‐of‐Module Assessment Task After Topic B After Topic C Format Standards Addressed Constructed response with rubric N‐CN.3, N‐CN.4, N‐CN.5, N‐CN.6, G‐CO.2, G‐CO.4, G‐CO.5 Constructed response with rubric N‐CN.4, N‐CN.5, N‐VM.10, N‐VM.11, N‐VM.12, G‐CO.2, G‐CO.4, G‐CO.5 Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
Name Mid‐Module Assessment Task
M1
PRECALCULUS Date 1. Let z1  2  2i and z2  1  i   3 1  i  . What is the modulus and argument of z1 ? Find a complex number w , written in the form w  a  ib , such that wz1  z2 . a.
b.
What is the modulus and argument of w ? c.
Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
Mid‐Module Assessment Task
M1
PRECALCULUS When the points z1 and z2 are plotted in the complex plane, what is the angle between the line d.
segment connecting the origin to z1 and the line segment connecting z2 to z1 ? What type of triangle is formed by the origin and the two points represented by the complex numbers z1 and z2 ? Find the complex number, v , closest to the origin that lies on the line segment connecting z1 and e.
z2 . Write v in rectangular form. Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
Mid‐Module Assessment Task
M1
PRECALCULUS 2. Let z be the complex number 2  3i lying in the complex plane. a. Write down the complex number that is the reflection of z across the horizontal axis. b. Write down the complex number that is the reflection of z across the vertical axis. Let m be the line through the origin of slope 1
in the complex plane. 2
c.
Write down a complex number, w , of modulus 1 that lies on m in the first quadrant. Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
d.
Mid‐Module Assessment Task
M1
PRECALCULUS What is the modulus of wz and how does it compare to the modulus of z ? First use properties of modulus to answer this question and then give a geometric explanation for what you observe. e.
When asked: 1
z ?” w
3
1
Paul gave the answer: arctan    arctan   , which he then computed to two decimal places. 2
2
“What is the argument of Provide a geometric explanation that yields Paul’s answer. Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
f.
Mid‐Module Assessment Task
M1
PRECALCULUS When asked: “What is the argument of 1
z ?” w
Mable did the complex number arithmetic and computed z  w . She then gave an answer in the a
b
form arctan   for some fraction
a
. What fraction did Mable find? Up to two decimal places, is b
Mable’s final answer the same as Paul’s? Write down the complex number (in rectangular form a  ib ) that is the reflection of z across line
m . g.
Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
A Progression Toward Mastery Assessment Task Item 1 Mid‐Module Assessment Task
M1
PRECALCULUS STEP 1 Missing or incorrect answer and little evidence of reasoning or application of mathematics to solve the problem. STEP 2
Missing or incorrect answer but evidence of some reasoning or application of mathematics to solve the problem. STEP 3
A correct answer with some evidence of reasoning or application of mathematics to solve the problem, or an incorrect answer with substantial evidence of solid reasoning or application of mathematics to solve the problem.
STEP 4 A correct answer supported by substantial evidence of solid reasoning or application of mathematics to solve the problem. a N‐CN.5 N‐CN.6 Neither answer is correct nor is there evidence to support that the student understands how to compute the modulus and argument. Correct method and answer for either the modulus or the argument OR correct method for both, but incorrect answers due to minor errors. Correct methods for both, but either modulus or argument is incorrect due to a minor error OR correct answers for both with no supporting work shown. Modulus AND argument computed correctly. Work shown to support their answer. b N‐CN.3 Does not attempt to divide z2 by z1 to find w. Attempts to divide z2 by z1 without applying the correct algorithm involving multiplication 1 in the form of the conjugate z1 divided by the conjugate of z1. Applies the division algorithm correctly AND shows work, but has minor mathematical errors leading to an incorrect final answer. Correct division algorithm, correct answer with sufficient work shown to demonstrate understanding of the process. Neither answer is correct nor is there evidence to support that the student understands how to compute the modulus and argument. Correct method and answer for either the modulus or the argument OR correct method for both, but incorrect answers due to minor errors. Correct methods for both, but either the modulus or the argument is incorrect due to a minor error OR correct answers for both with no supporting work shown. Modulus AND argument are computed correctly for their answer to part b. Work shown to support answer. NOTE: Student can earn full points for this even if the answer to b was incorrect. Little or no attempt is made to identify the triangle and requested angle measure. May identify the triangle as isosceles but cannot determine the angle between the two complex numbers whose vertex is at the origin. Explanation fails to connect multiplication Identifies the triangle as isosceles or equilateral, but may not indicate the requested angle measurement or gives an incorrect angle measurement. Explanation does not Identifies the triangle as equilateral and gives the measure of angle as 60°. Explanation clearly connects multiplication with the correct transformations by explaining that z2 is the c N‐CN.5 N‐CN.6 d N‐CN.4 N‐CN.5 G‐CO.2 G‐CO.4 G‐CO.5 Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
Mid‐Module Assessment Task
M1
PRECALCULUS with transformations. Explanation may include a comparison of the moduli of z1 and z2. Answer may include a sketch to support the answer. fully address the connection between multiplication and transformations. Explanation may include a comparison of the moduli of z1 and z2. Answer may include a sketch to support the answer. image of z1 achieved by rotating z1 by the arg(w) and no dilation since |w|= 1. Answer may be supported with a sketch. Little or no attempt to find v. May attempt to sketch the situation, but more than one misconception or mathematical error leads to an incorrect or incomplete solution. Finds v correctly, but there is little or no explanation or work explaining why v is the midpoint of the line segment OR identifies that v would be at the midpoint, but fails to compute it correctly. Averages z1 and z2 to find v AND clearly explains why using a geometric argument regarding v’s location on the perpendicular bisector of the triangle. a N‐CN.3 G‐CO.2 Both real AND imaginary parts are incorrect. Real OR imaginary part is incorrect. Correct answer. No explanation. Correct answer. Identifies it as the conjugate. b N‐CN.5 G‐CO.2 Both real AND imaginary parts are incorrect. Real OR imaginary part is incorrect. Correct answer. No explanation. Correct answer. Explains that the real part is the opposite but the imaginary part stays the same. c N‐CN.4 G‐CO.2 Answer is not a complex number OR is a complex number with both an incorrect modulus and argument. There is little or no supporting work shown. Incorrect answer with little evidence of correct reasoning (solution may fail to address modulus of 1 but be a complex number on the line m OR may have a modulus of 1, but not be a complex number on the line m). Correct answer with limited reasoning or work to support the answer OR correct reasoning but minor mathematical errors lead to an incorrect solution. Correct answer with work shown to support their approach. Reasoning could use the polar form of a complex number OR apply proportional reasoning to find w with the correct argument and modulus. d N‐CN.4 G‐CO.5 Incorrect answer with little or no work shown. Correct answer, but does not include a geometric or modulus operation explanation. Correct answer, but one of the two explanations is limited or missing OR incorrect answer due to a minor error with sufficient evidence to support understanding of both the modulus and geometric arguments. Correct answer with work shown to clearly support both explanations (properties of modulus and geometric). e N‐CN.4 2 Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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Mid‐Module Assessment Task
M1
PRECALCULUS e N‐CN.5 N‐CN.6 Little or no work. Explanation fails to address transformations in a meaningful way. Explanation may include references to rotations and dilations does not clearly address the fact that multiplication by 1/w represents a clockwise rotation of arg(w). Identifies arg (z) and arg(w), explains that multiplication by 1/w would create a clockwise rotation, but the explanation lacks a clear reason why the two should be subtracted or contains other minor errors. Explains both correct the rotation and lack of dilation since |w| = 1. Identifies arg(z) and arg(w) in their explanation AND supports why their difference in the solution. May include a sketch. f N‐CN.3 N‐CN.5 Both z/w and arg(z/w) are incorrect due to major misconceptions or calculation errors. May argue incorrectly that the arguments in e and f should be different. Either z/w or arg(z/w) is incorrect due to mathematical errors. Should indicate that both arguments should be the same. Correctly computes z/w and arg(z/w), but fails to compare the arguments in part d and e or explain why they should be the same. Correct answer. Computes both arguments to two decimal places. Work shown uses appropriate notation AND sufficient steps to follow the solution. g N‐CN.4 G‐CO.4 Little or no attempt to solve the problem. Explains an approach the would partially accomplish a correct solution and supports it with correct work OR explains a correct approach, but makes limited progress on a correct solution due to major errors. Explains, but may not be able to execute an approach that would yield a correct solution. Work is limited and may contain minor errors. Explains AND executes an approach that yields a correct solution. Work is supported both verbally AND symbolically with proper terminology and notation. Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
Mid‐Module Assessment Task
M1
PRECALCULUS Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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Mid‐Module Assessment Task
M1
PRECALCULUS Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
Mid‐Module Assessment Task
M1
PRECALCULUS Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
Mid‐Module Assessment Task
M1
PRECALCULUS Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
Mid‐Module Assessment Task
M1
PRECALCULUS Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
End‐of‐Module Assessment Task
M1
PRECALCULUS Name Date 1 k 
 for a fixed positive number
0 k 
1. Consider the transformation on the plane given by the 2  2 matrix 
k . a.
Draw a sketch of the image of the unit square under this transformation (the unit square has vertices
 0,0 , 1,0 ,  0,1 , and 1,1 ). Be sure to label all four vertices of the image figure. b.
What is the area of the image parallelogram? Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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End‐of‐Module Assessment Task
M1
PRECALCULUS  x
 y
 2
 3
Find the coordinates of a point   whose image under the transformation is   . c.
1 k 
1
 is applied once to the point   , and then once to the image point, and 0 k 
1
The transformation 
d.
then once to the image of the image point, and then once to the image of the image of the image 1
1
point, and so on. What are the coordinates of ten‐fold image of the point   ? Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
End‐of‐Module Assessment Task
M1
PRECALCULUS  cos 1  sin 1 
 .  sin 1 cos 1 
2. Consider the transformation given by 
a.
 x
 y
Describe the geometric effect of applying this transformation to a point   in the plane. b.
 x
 y
Describe the geometric effect of applying this transformation to a point   in the plane twice: once to the point, and then once to its image. c.
Use part (b) to prove cos  2   cos 1  sin 1 and sin  2   2sin 1 cos 1 . 2
2
Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
End‐of‐Module Assessment Task
M1
PRECALCULUS A Progression Toward Mastery Assessment Task Item 1 STEP 1 Missing or incorrect answer and little evidence of reasoning or application of mathematics to solve the problem. STEP 2
Missing or incorrect answer but evidence of some reasoning or application of mathematics to solve the problem. STEP 3
A correct answer with some evidence of reasoning or application of mathematics to solve the problem, or an incorrect answer with substantial evidence of solid reasoning or application of mathematics to solve the problem.
STEP 4 A correct answer supported by substantial evidence of solid reasoning or application of mathematics to solve the problem. a N‐VM.11 N‐VM.12 G‐CO.2 G‐CO.5 Solution doesn’t apply matrix multiplication or transformations to determine the coordinates of the resulting image. Sketch is missing. Two or more coordinates of the image are incorrect and the sketch of the image is incomplete or poorly labeled OR the image is a parallelogram with now work shown and no vertices labeled. Coordinates of the image are correct, but the sketch of the image may be slightly inaccurate. Work to support the calculation of the image coordinates is limited OR three out of four coordinates correct and sketch accurately reflects the student’s coordinates. Applies matrix multiplication each coordinate of the unit square to get the image coordinates. Draws a fairly accurate sketch of a parallelogram with vertices correctly labeled. Values for k will vary, but the resulting image should look like a parallelogram and the distance k in the vertical and horizontal direction should appear equal. b N‐VM.12 G‐CO.2 Does not compute the area of a parallelogram or the figure they sketched correctly. Computes the area of their figure correctly, but does not use determinant of the 2 x 2 matrix in their calculation. Computes the area of their figure using the determinant of the 2 x 2 matrix, but the solution may contain minor errors. Computes area of the parallelogram correctly using a determinant. Work shows understanding that the area of the image is the product of the area of the original figure and the absolute value of the determinant of the transformation matrix. c No solution provided OR work is unrelated to the standards addressed in this problem. Incorrect solution or set up of the original matrix equation. Limited evidence that the student understands that the solution to the Creates a correct matrix equation to solve for the point and translates the equation to a system of linear equations. Work shown may be Creates a correct matrix equation to solve for the point. Translates the equation to a system of linear equations AND solves the system N‐VM.10 N‐VM.11 G‐CO.2 Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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End‐of‐Module Assessment Task
M1
PRECALCULUS matrix equation will find the point in question OR correct matrix equation and no additional work OR correct system of linear equations and no additional work. incomplete and final answer may contain minor errors OR correct solution, but the matrix equation or the system of equations is missing from their solution. Very little work shown to provide evidence of student thinking. correctly. Work shown is organized in a manner that is easy to follow and uses proper mathematical notation. Student solution does not correctly apply the transformation one time. Student does not attempt a generalization for the 10‐fold image. Student solution does not correctly apply the transformation more than one time. Student may attempt to generalize to the 10‐fold image, but their answer contains major conceptual errors. Student solution provides evidence that the student understood the problem and observed patterns, but minor errors prevent a correct solution for the 10‐fold image OR student solution shows correct repeated application of the transformation at least three times, but the student is unable to extend the pattern to the 10‐fold image. Correct solution for the 10‐fold image. Student solution provides enough evidence AND explanation to clearly illustrate how they observed and extended the pattern. Does not recognize the transformation as a rotation of the point about the origin. Identifies the transformation as a rotation, but cannot correctly state the direction or the angle measure. Correctly identifies the transformation as a rotation about the origin, but the answer contains an error, such as the wrong direction or the wrong angle measurement. Correctly identifies the transformation as a counterclockwise rotation about the origin through an angle of 1 radian. Identifies the transformation as a rotation, but the solution does not make it clear nd
that the 2 rotation applies to the image of the original point OR identifies the transformation as an additional rotation, but the answer contains two or more errors. Correctly identifies the repeated transformation as an additional rotation, but the answer contains no more than one error. Correctly identifies the repeated transformation as a rotation of the image of the point another 1 radian clockwise about the origin for a total of 2 radians. d N‐VM.11 2 a N‐VM.11 N‐VM.12 N‐CN.4 N‐CN.5 G‐CO.2 G‐CO.4 Does not identify the b repeated transformation as a rotation. N‐VM.11 N‐VM.12 N‐CN.4 N‐CN.5 G‐CO.2 G‐CO.4 Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
End‐of‐Module Assessment Task
M1
PRECALCULUS c N‐CN.4 N‐CN.5 G‐CO.2 Little or no attempt at multiplying the point (x,y) by either of the rotation matrices. Sets up and attempts the necessary matrix multiplications, but solution has too many major errors OR too little work for the student to make significant progress on the proof. Solution includes multiplication of (x,y) by the original rotation matrix twice AND multiplication of (x,y) by the 2‐radian rotation matrix. Fails to equate the two answers to finish the proof. Solution may contain minor computation errors. The solution details multiplication by the original rotation matrix twice, compares that result to multiplication by the 2‐radian rotation matrix, AND equates the two answers to verify the identities. Students use correct notation AND their solution illustrates their thinking clearly. The solution is free from minor errors. Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
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NYS COMMON CORE MATHEMATICS CURRICULUM
End‐of‐Module Assessment Task
M1
PRECALCULUS Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
5/11/13 28
NYS COMMON CORE MATHEMATICS CURRICULUM
End‐of‐Module Assessment Task
M1
PRECALCULUS Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
5/11/13 29
NYS COMMON CORE MATHEMATICS CURRICULUM
End‐of‐Module Assessment Task
M1
PRECALCULUS Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
5/11/13 30
NYS COMMON CORE MATHEMATICS CURRICULUM
End‐of‐Module Assessment Task
M1
PRECALCULUS Module 1: Date: © 2012 Common Core, Inc. All rights reserved. commoncore.org Complex Numbers and Transformations
5/11/13 31
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© 2012 Common Core, Inc. All rights reserved. commoncore.org