Real Zeros of Polynomial Functions
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Lesson 1: Solutions to Polynomial Equations
NYS COMMON CORE MATHEMATICS CURRICULUM Lesson 1 M3 PRECALCULUS AND ADVANCED TOPICS Lesson 1: Solutions to Polynomial Equations Classwork Opening Exercise How many solutions are there to the equation 푥2 = 1? Explain how you know. Example 1: Prove that a Quadratic Equation Has Only Two Solutions over the Set of Complex Numbers Prove that 1 and −1 are the only solutions to the equation 푥2 = 1. Let 푥 = 푎 + 푏푖 be a complex number so that 푥2 = 1. a. Substitute 푎 + 푏푖 for 푥 in the equation 푥2 = 1. b. Rewrite both sides in standard form for a complex number. c. Equate the real parts on each side of the equation, and equate the imaginary parts on each side of the equation. d. Solve for 푎 and 푏, and find the solutions for 푥 = 푎 + 푏푖. Lesson 1: Solutions to Polynomial Equations S.1 This work is licensed under a This work is derived from Eureka Math ™ and licensed by Great Minds. ©2015 Great Minds. eureka-math.org This file derived from PreCal-M3-TE-1.3.0-08.2015 Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. NYS COMMON CORE MATHEMATICS CURRICULUM Lesson 1 M3 PRECALCULUS AND ADVANCED TOPICS Exercises Find the product. 1. (푧 − 2)(푧 + 2) 2. (푧 + 3푖)(푧 − 3푖) Write each of the following quadratic expressions as the product of two linear factors. 3. 푧2 − 4 4. 푧2 + 4 5. 푧2 − 4푖 6. 푧2 + 4푖 Lesson 1: Solutions to Polynomial Equations S.2 This work is licensed under a This work is derived from Eureka Math ™ and licensed by Great Minds. -
Lesson 1.2 – Linear Functions Y M a Linear Function Is a Rule for Which Each Unit 1 Change in Input Produces a Constant Change in Output
Lesson 1.2 – Linear Functions y m A linear function is a rule for which each unit 1 change in input produces a constant change in output. m 1 The constant change is called the slope and is usually m 1 denoted by m. x 0 1 2 3 4 Slope formula: If (x1, y1)and (x2 , y2 ) are any two distinct points on a line, then the slope is rise y y y m 2 1 . (An average rate of change!) run x x x 2 1 Equations for lines: Slope-intercept form: y mx b m is the slope of the line; b is the y-intercept (i.e., initial value, y(0)). Point-slope form: y y0 m(x x0 ) m is the slope of the line; (x0, y0 ) is any point on the line. Domain: All real numbers. Graph: A line with no breaks, jumps, or holes. (A graph with no breaks, jumps, or holes is said to be continuous. We will formally define continuity later in the course.) A constant function is a linear function with slope m = 0. The graph of a constant function is a horizontal line, and its equation has the form y = b. A vertical line has equation x = a, but this is not a function since it fails the vertical line test. Notes: 1. A positive slope means the line is increasing, and a negative slope means it is decreasing. 2. If we walk from left to right along a line passing through distinct points P and Q, then we will experience a constant steepness equal to the slope of the line. -
Use of Iteration Technique to Find Zeros of Functions and Powers of Numbers
USE OF ITERATION TECHNIQUE TO FIND ZEROS OF FUNCTIONS AND POWERS OF NUMBERS Many functions y=f(x) have multiple zeros at discrete points along the x axis. The location of most of these zeros can be estimated approximately by looking at a graph of the function. Simple roots are the ones where f(x) passes through zero value with finite value for its slope while double roots occur for functions where its derivative also vanish simultaneously. The standard way to find these zeros of f(x) is to use the Newton-Raphson technique or a variation thereof. The procedure is to expand f(x) in a Taylor series about a starting point starting with the original estimate x=x0. This produces the iteration- 2 df (xn ) 1 d f (xn ) 2 0 = f (xn ) + (xn+1 − xn ) + (xn+1 − xn ) + ... dx 2! dx2 for which the function vanishes. For a function with a simple zero near x=x0, one has the iteration- f (xn ) xn+1 = xn − with x0 given f ′(xn ) For a double root one needs to keep three terms in the Taylor series to yield the iteration- − f ′(x ) + f ′(x)2 − 2 f (x ) f ′′(x ) n n n ∆xn+1 = xn+1 − xn = f ′′(xn ) To demonstrate how this procedure works, take the simple polynomial function- 2 4 f (x) =1+ 2x − 6x + x Its graph and the derivative look like this- There appear to be four real roots located near x=-2.6, -0.3, +0.7, and +2.2. None of these four real roots equal to an integer, however, they correspond to simple zeros near the values indicated. -
9 Power and Polynomial Functions
Arkansas Tech University MATH 2243: Business Calculus Dr. Marcel B. Finan 9 Power and Polynomial Functions A function f(x) is a power function of x if there is a constant k such that f(x) = kxn If n > 0, then we say that f(x) is proportional to the nth power of x: If n < 0 then f(x) is said to be inversely proportional to the nth power of x. We call k the constant of proportionality. Example 9.1 (a) The strength, S, of a beam is proportional to the square of its thickness, h: Write a formula for S in terms of h: (b) The gravitational force, F; between two bodies is inversely proportional to the square of the distance d between them. Write a formula for F in terms of d: Solution. 2 k (a) S = kh ; where k > 0: (b) F = d2 ; k > 0: A power function f(x) = kxn , with n a positive integer, is called a mono- mial function. A polynomial function is a sum of several monomial func- tions. Typically, a polynomial function is a function of the form n n−1 f(x) = anx + an−1x + ··· + a1x + a0; an 6= 0 where an; an−1; ··· ; a1; a0 are all real numbers, called the coefficients of f(x): The number n is a non-negative integer. It is called the degree of the polynomial. A polynomial of degree zero is just a constant function. A polynomial of degree one is a linear function, of degree two a quadratic function, etc. The number an is called the leading coefficient and a0 is called the constant term. -
Polynomials.Pdf
POLYNOMIALS James T. Smith San Francisco State University For any real coefficients a0,a1,...,an with n $ 0 and an =' 0, the function p defined by setting n p(x) = a0 + a1 x + AAA + an x for all real x is called a real polynomial of degree n. Often, we write n = degree p and call an its leading coefficient. The constant function with value zero is regarded as a real polynomial of degree –1. For each n the set of all polynomials with degree # n is closed under addition, subtraction, and multiplication by scalars. The algebra of polynomials of degree # 0 —the constant functions—is the same as that of real num- bers, and you need not distinguish between those concepts. Polynomials of degrees 1 and 2 are called linear and quadratic. Polynomial multiplication Suppose f and g are nonzero polynomials of degrees m and n: m f (x) = a0 + a1 x + AAA + am x & am =' 0, n g(x) = b0 + b1 x + AAA + bn x & bn =' 0. Their product fg is a nonzero polynomial of degree m + n: m+n f (x) g(x) = a 0 b 0 + AAA + a m bn x & a m bn =' 0. From this you can deduce the cancellation law: if f, g, and h are polynomials, f =' 0, and fg = f h, then g = h. For then you have 0 = fg – f h = f ( g – h), hence g – h = 0. Note the analogy between this wording of the cancellation law and the corresponding fact about multiplication of numbers. One of the most useful results about integer multiplication is the unique factoriza- tion theorem: for every integer f > 1 there exist primes p1 ,..., pm and integers e1 em e1 ,...,em > 0 such that f = pp1 " m ; the set consisting of all pairs <pk , ek > is unique. -
5.2 Polynomial Functions 5.2 Polynomialfunctions
5.2 Polynomial Functions 5.2 PolynomialFunctions This is part of 5.1 in the current text In this section, you will learn about the properties, characteristics, and applications of polynomial functions. Upon completion you will be able to: • Recognize the degree, leading coefficient, and end behavior of a given polynomial function. • Memorize the graphs of parent polynomial functions (linear, quadratic, and cubic). • State the domain of a polynomial function, using interval notation. • Define what it means to be a root/zero of a function. • Identify the coefficients of a given quadratic function and he direction the corresponding graph opens. • Determine the verte$ and properties of the graph of a given quadratic function (domain, range, and minimum/maximum value). • Compute the roots/zeroes of a quadratic function by applying the quadratic formula and/or by factoring. • !&etch the graph of a given quadratic function using its properties. • Use properties of quadratic functions to solve business and social science problems. DescribingPolynomialFunctions ' polynomial function consists of either zero or the sum of a finite number of non-zero terms, each of which is the product of a number, called the coefficient of the term, and a variable raised to a non-negative integer (a natural number) power. Definition ' polynomial function is a function of the form n n ) * f(x =a n x +a n ) x − +...+a * x +a ) x+a +, − wherea ,a ,...,a are real numbers andn ) is a natural number. � + ) n ≥ In a previous chapter we discussed linear functions, f(x =mx=b , and the equation of a horizontal line, y=b . -
Factors, Zeros, and Solutions
Mathematics Instructional Plan – Algebra II Factors, Zeros, and Solutions Strand: Functions Topic: Exploring relationships among factors, zeros, and solutions Primary SOL: AII.8 The student will investigate and describe the relationships among solutions of an equation, zeros of a function, x-intercepts of a graph, and factors of a polynomial expression. Related SOL: AII.1d, AII.4b, AII.7b Materials Zeros and Factors activity sheet (attached) Matching Cards activity sheet (attached) Sorting Challenge activity sheet (attached) Graphing utility Colored paper Graph paper Vocabulary factor, fundamental theorem of algebra, imaginary numbers, multiplicity, polynomial, rate of change, real numbers, root, slope, solution, x-intercept, y-intercept, zeros of a function Student/Teacher Actions: What should students be doing? What should teachers be doing? Time: 90 minutes 1. Have students solve the equation 3x + 5 = 11. Then, have students set the left side of the equation equal to zero. Tell students to replace zero with y and consider the line y = 3x − 6. Instruct them to graph the line on graph paper. Review the terms slope, x- intercept, and y-intercept. Then, have them perform the same procedure (i.e., solve, set left side equal to zero, replace zero with y, and graph) for the equation −2x + 6 = 4. They should notice that in both cases, the x-intercept is the same as the solution to the equation. 2. Students explored factoring of zeros in Algebra I. Use the following practice problem to review: y = x2 + 4x + 3. Facilitate a discussion with students using the following questions: o “What is the first step in graphing the given line?” o “How do you find the factors of the line?” o “What role does zero play in graphing the line?” o “In how many ‘places’ did this line cross (intersect) the x-axis?” o “When the function crosses the x-axis, what is the value of y?” o “What is the significance of the x-intercepts of the graphs?” 3. -
Elementary Functions, Student's Text, Unit 21
DOCUMENT RESUME BD 135 629 SE 021 999 AUTHOR Allen, Frank B.; And Others TITLE Elementary Functions, Student's Text, Unit 21. INSTITUTION Stanford Univ., Calif. School Mathematics Study Group. SPONS AGENCY National Science Foundation, Washington, D.C. PUB DATE 61 NOTE 398p.; For related documents, see SE 021 987-022 002 and ED 130 870-877; Contains occasional light type EDRS PRICE MF-$0.83 HC-$20.75 Plus Postage. DESCRIPTO2S *Curriculum; Elementary Secondary Education; Instruction; *Instructional Materials; Mathematics Education; *Secondary School Mathematics; *Textbooks IDENTIFIERS *Functions (Mathematics); *School Mathematics Study Group ABSTRACT Unit 21 in the SMSG secondary school mathematics series is a student text covering the following topics in elementary functions: functions, polynomial functions, tangents to graphs of polynomial functions, exponential and logarithmic functions, and circular functions. Appendices discuss set notation, mathematical induction, significance of polynomials, area under a polynomial graph, slopes of area functions, the law of growth, approximation and computation of e raised to the x power, an approximation for ln x, measurement of triangles, trigonometric identities and equations, and calculation of sim x and cos x. (DT) *********************************************************************** Documents acquired by ERIC include many informal unpublished * materials not available from other sources. ERIC makes every effort * * to obtain the best copy available. Nevertheless, items of marginal * * reproducibility are often encountered and this affects the quality * * of the microfiche and hardcopy reproductions ERIC makes available * * via the ERIC Document Reproduction Service (EDRS). EDRS is not * responsible for the quality of the original document. Reproductions * * supplied by EDRS are the best that can be made from the original. -
Applications of Derivatives
5128_Ch04_pp186-260.qxd 1/13/06 12:35 PM Page 186 Chapter 4 Applications of Derivatives n automobile’s gas mileage is a function of many variables, including road surface, tire Atype, velocity, fuel octane rating, road angle, and the speed and direction of the wind. If we look only at velocity’s effect on gas mileage, the mileage of a certain car can be approximated by: m(v) ϭ 0.00015v 3 Ϫ 0.032v 2 ϩ 1.8v ϩ 1.7 (where v is velocity) At what speed should you drive this car to ob- tain the best gas mileage? The ideas in Section 4.1 will help you find the answer. 186 5128_Ch04_pp186-260.qxd 1/13/06 12:36 PM Page 187 Section 4.1 Extreme Values of Functions 187 Chapter 4 Overview In the past, when virtually all graphing was done by hand—often laboriously—derivatives were the key tool used to sketch the graph of a function. Now we can graph a function quickly, and usually correctly, using a grapher. However, confirmation of much of what we see and conclude true from a grapher view must still come from calculus. This chapter shows how to draw conclusions from derivatives about the extreme val- ues of a function and about the general shape of a function’s graph. We will also see how a tangent line captures the shape of a curve near the point of tangency, how to de- duce rates of change we cannot measure from rates of change we already know, and how to find a function when we know only its first derivative and its value at a single point. -
Optimization Algorithms on Matrix Manifolds
00˙AMS September 23, 2007 © Copyright, Princeton University Press. No part of this book may be distributed, posted, or reproduced in any form by digital or mechanical means without prior written permission of the publisher. Chapter Six Newton’s Method This chapter provides a detailed development of the archetypal second-order optimization method, Newton’s method, as an iteration on manifolds. We propose a formulation of Newton’s method for computing the zeros of a vector field on a manifold equipped with an affine connection and a retrac tion. In particular, when the manifold is Riemannian, this geometric Newton method can be used to compute critical points of a cost function by seeking the zeros of its gradient vector field. In the case where the underlying space is Euclidean, the proposed algorithm reduces to the classical Newton method. Although the algorithm formulation is provided in a general framework, the applications of interest in this book are those that have a matrix manifold structure (see Chapter 3). We provide several example applications of the geometric Newton method for principal subspace problems. 6.1 NEWTON’S METHOD ON MANIFOLDS In Chapter 5 we began a discussion of the Newton method and the issues involved in generalizing such an algorithm on an arbitrary manifold. Sec tion 5.1 identified the task as computing a zero of a vector field ξ on a Riemannian manifold equipped with a retraction R. The strategy pro M posed was to obtain a new iterate xk+1 from a current iterate xk by the following process. 1. Find a tangent vector ηk Txk such that the “directional derivative” of ξ along η is equal to ∈ ξ. -
Lesson 11 M1 ALGEBRA II
NYS COMMON CORE MATHEMATICS CURRICULUM Lesson 11 M1 ALGEBRA II Lesson 11: The Special Role of Zero in Factoring Student Outcomes . Students find solutions to polynomial equations where the polynomial expression is not factored into linear factors. Students construct a polynomial function that has a specified set of zeros with stated multiplicity. Lesson Notes This lesson focuses on the first part of standard A-APR.B.3, identifying zeros of polynomials presented in factored form. Although the terms root and zero are interchangeable, for consistency only the term zero is used throughout this lesson and in later lessons. The second part of the standard, using the zeros to construct a rough graph of a polynomial function, is delayed until Lesson 14. The ideas that begin in this lesson continue in Lesson 19, in which students will be able to associate a zero of a polynomial function to a factor in the factored form of the associated polynomial as a consequence of the remainder theorem, and culminate in Lesson 39, in which students apply the fundamental theorem of algebra to factor polynomial expressions completely over the complex numbers. Classwork Scaffolding: Here is an alternative opening Opening Exercise (12 minutes) activity that may better illuminate the special role of Opening Exercise zero. ퟐ ퟐ Find all solutions to the equation (풙 + ퟓ풙 + ퟔ)(풙 − ퟑ풙 − ퟒ) = ퟎ. For each equation, list some possible values for 푥 and 푦. The main point of this opening exercise is for students to recognize and then formalize that the statement “If 푎푏 = 0, then 푎 = 0 or 푏 = 0” applies not only when 푎 and 푏 are 푥푦 = 10, 푥푦 = 1, numbers or linear functions (which we used when solving a quadratic equation), but also 푥푦 = −1, 푥푦 = 0 applies to cases where 푎 and 푏 are polynomial functions of any degree. -
Root-Finding 3.1 Physical Problems
Physics 200 Lecture 3 Root-Finding Lecture 3 Physics 200 Laboratory Monday, February 14th, 2011 The fundamental question answered by this week's lab work will be: Given a function F (x), find some/all of the values xi for which F (xi) = 0. It's a f g modest goal, and we will use a simple method to solve the problem. But, as we shall see, there are a wide range of physical problems that have, at their heart, just such a question. We'll start in the simplest, polynomial setting, and work our way up to the \shooting" method. 3.1 Physical Problems We'll set up some direct applications of root-finding with familiar physical examples, and then shift gears and define a numerical root-finding routine that can be used to solve a very different set of problems. 3.1.1 Orbital Motion In two-dimensions, with a spherically symmetric potential (meaning here that V (x; y; z) = V (r), a function of a single variable, r x2 + y2 + z2, ≡ the distance to the origin) we can use circular coordinates to write the total p energy of a test particle moving under the influence of this potential as 1 E = m r_2 + r2 φ_2 + V (r): (3.1) 2 Conservation of momentum tells us that the z-component of angular mo- 2 mentum is conserved, with Lz = (r p) = m r φ_, so we can rewrite the × z 1 of 13 3.1. PHYSICAL PROBLEMS Lecture 3 energy as: 1 1 L2 E = m r_2 + z + V (r) (3.2) 2 2 m r2 ≡U(r) where U(r) defines an “effective potential"| { we{z have} turned a two-dimensional problem into a one-dimensional problem for the coordinate r, and an effec- tive potential that governs the motion in this setting.