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  2. 2. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES CalculusFourth Edition ROBERT T. SMITH Millersville University of Pennsylvania ROLAND B. MINTON Roanoke College i
  3. 3. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES CALCULUS, FOURTH EDITION Published by McGraw-Hill, a business unit of The McGraw-Hill Companies, Inc., 1221 Avenue of the Americas, New York, NY 10020. Copyright c 2012 by The McGraw-Hill Companies, Inc. All rights reserved. Previous editions c 2008, 2002, and 2000. No part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written consent of The McGraw-Hill Companies, Inc., including, but not limited to, in any network or other electronic storage or transmission, or broadcast for distance learning. Some ancillaries, including electronic and print components, may not be available to customers outside the United States. This book is printed on acid-free paper. 1 2 3 4 5 6 7 8 9 0 QVR/QVR 1 0 9 8 7 6 5 4 3 2 1 ISBN 9780073383118 MHID 0073383112 Vice President, Editor-in-Chief: Marty Lange Vice President, EDP: Kimberly Meriwether David Senior Director of Development: Kristine Tibbetts Editorial Director: Stewart K. Mattson Sponsoring Editor: John R. Osgood Developmental Editor: Eve L. Lipton Marketing Manager: Kevin M. Ernzen Lead Project Manager: Peggy J. Selle Senior Buyer: Sandy Ludovissy Lead Media Project Manager: Judi David Senior Designer: Laurie B. Janssen Cover Designer: Ron Bissell Cover Image: c Gettyimages/George Diebold Photography Senior Photo Research Coordinator: John C. Leland Compositor: Aptara, Inc. Typeface: 10/12 Times Roman Printer: Quad/Graphics All credits appearing on page or at the end of the book are considered to be an extension of the copyright page. Library of Congress Cataloging-in-Publication Data Smith, Robert T. (Robert Thomas), 1955- Calculus / Robert T. Smith, Roland B. Minton. 4th ed. p. cm. Includes index. ISBN 9780073383118ISBN 0073383112 (hard copy : alk. paper) 1. Transcendental functionsTextbooks. 2. CalculusTextbooks. I. Minton, Roland B., 1956 II. Title. QA353.S649 2012 515 .22dc22 2010030314 www.mhhe.com ii
  4. 4. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES DEDICATION To Pam, Katie and Michael To Jan, Kelly and Greg And in memory of our parents: George and Anne Smith and Paul and Mary Frances Minton iii
  5. 5. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES About the Authors Robert T. Smith is Professor of Mathematics and Dean of the School of Science and MathematicsatMillersvilleUniversityofPennsylvania,wherehehasbeenafacultymember since 1987. Prior to that, he was on the faculty at Virginia Tech. He earned his Ph.D. in mathematics from the University of Delaware in 1982. Professor Smiths mathematical interests are in the application of mathematics to prob- lemsinengineeringandthephysicalsciences.Hehaspublishedanumberofresearcharticles on the applications of partial differential equations as well as on computational problems in x-ray tomography. He is a member of the American Mathematical Society, the Mathematical Association of America, and the Society for Industrial and Applied Mathematics. Professor Smith lives in Lancaster, Pennsylvania, with his wife Pam, his daughter Katie and his son Michael. His ongoing extracurricular goal is to learn to play golf well enough to not come in last in his annual mathematicians/statisticians tournament. Roland B. Minton is Professor of Mathematics and Chair of the Department of Mathemat- ics, Computer Science and Physics at Roanoke College, where he has taught since 1986. Prior to that, he was on the faculty at Virginia Tech. He earned his Ph.D. from Clemson University in 1982. He is the recipient of Roanoke College awards for teaching excellence and professional achievement, as well as the 2005 Virginia Outstanding Faculty Award and the 2008 George Polya Award for mathematics exposition. Professor Mintons current research program is in the mathematics of golf, especially the analysis of ShotLink statistics. He has published articles on various aspects of sports science, and co-authored with Tim Pennings an article on Pennings dog Elvis and his ability to solve calculus problems. He is co-author of a technical monograph on control theory. He has supervised numerous independent studies and held workshops for local high school teachers. He is an active member of the Mathematical Association of America. Professor Minton lives in Salem, Virginia, with his wife Jan and occasionally with his daughter Kelly and son Greg when they visit. He enjoys playing golf when time permits and watching sports events even when time doesnt permit. Jan also teaches at Roanoke College and is very active in mathematics education. In addition to Calculus: Early Transcendental Functions, Professors Smith and Minton are also coauthors of Calculus: Concepts and Connections c 2006, and three earlier books for McGraw-Hill Higher Education. Earlier editions of Calculus have been translated into Spanish, Chinese and Korean and are in use around the world. iv
  6. 6. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES Brief Table of Contents CHAPTER 0 .. Preliminaries 1 CHAPTER 1 .. Limits and Continuity 47 CHAPTER 2 .. Differentiation 107 CHAPTER 3 .. Applications of Differentiation 173 CHAPTER 4 .. Integration 251 CHAPTER 5 .. Applications of the Definite Integral 315 CHAPTER 6 .. Exponentials, Logarithms and Other Transcendental Functions 375 CHAPTER 7 .. Integration Techniques 421 CHAPTER 8 .. First-Order Differential Equations 491 CHAPTER 9 .. Infinite Series 531 CHAPTER 10 .. Parametric Equations and Polar Coordinates 625 CHAPTER 11 .. Vectors and the Geometry of Space 687 CHAPTER 12 .. Vector-Valued Functions 749 CHAPTER 13 .. Functions of Several Variables and Partial Differentiation 809 CHAPTER 14 .. Multiple Integrals 901 CHAPTER 15 .. Vector Calculus 977 CHAPTER 16 .. Second-Order Differential Equations 1073 APPENDIX A .. Proofs of Selected Theorems A-1 APPENDIX B .. Answers to Odd-Numbered Exercises A-13 v
  7. 7. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 10, 2011 8:35 LT (Late Transcendental) CONFIRMING PAGES Table of Contents Seeing the Beauty and Power of Mathematics xiii Applications Index xxiv CHAPTER 0 .. Preliminaries 1 0.1 The Real Numbers and the Cartesian Plane 2 . The Real Number System and Inequalities . The Cartesian Plane 0.2 Lines and Functions 9 . Equations of Lines . Functions 0.3 Graphing Calculators and Computer Algebra Systems 21 0.4 Trigonometric Functions 27 0.5 Transformations of Functions 36 CHAPTER 1 .. Limits and Continuity 47 1.1 A Brief Preview of Calculus: Tangent Lines and the Length of a Curve 47 1.2 The Concept of Limit 52 1.3 Computation of Limits 59 1.4 Continuity and Its Consequences 68 . The Method of Bisections 1.5 Limits Involving Infinity; Asymptotes 78 . Limits at Infinity 1.6 Formal Definition of the Limit 87 . Exploring the Definition of Limit Graphically . Limits Involving Infinity 1.7 Limits and Loss-of-Significance Errors 98 . Computer Representation of Real Numbers CHAPTER 2 .. Differentiation 107 2.1 Tangent Lines and Velocity 107 . The General Case . Velocity 2.2 The Derivative 118 . Alternative Derivative Notations . Numerical Differentiation vi
  8. 8. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES Table of Contents vii 2.3 Computation of Derivatives: The Power Rule 127 . The Power Rule . General Derivative Rules . Higher Order Derivatives . Acceleration 2.4 The Product and Quotient Rules 135 . Product Rule . Quotient Rule . Applications 2.5 The Chain Rule 142 2.6 Derivatives of Trigonometric Functions 147 . Applications 2.7 Implicit Differentiation 155 2.8 The Mean Value Theorem 162 CHAPTER 3 .. Applications of Differentiation 173 3.1 Linear Approximations and Newtons Method 174 . Linear Approximations . Newtons Method 3.2 Maximum and Minimum Values 185 3.3 Increasing and Decreasing Functions 195 . What You See May Not Be What You Get 3.4 Concavity and the Second Derivative Test 203 3.5 Overview of Curve Sketching 212 3.6 Optimization 223 3.7 Related Rates 234 3.8 Rates of Change in Economics and the Sciences 239 CHAPTER 4 .. Integration 251 4.1 Antiderivatives 252 4.2 Sums and Sigma Notation 259 . Principle of Mathematical Induction 4.3 Area 266 4.4 The Definite Integral 273 . Average Value of a Function 4.5 The Fundamental Theorem of Calculus 284 4.6 Integration by Substitution 292 . Substitution in Definite Integrals 4.7 Numerical Integration 298 . Simpsons Rule . Error Bounds for Numerical Integration CHAPTER 5 .. Applications of the Definite Integral 315 5.1 Area Between Curves 315 5.2 Volume: Slicing, Disks and Washers 324 . Volumes by Slicing . The Method of Disks . The Method of Washers
  9. 9. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES viii Table of Contents 5.3 Volumes by Cylindrical Shells 338 5.4 Arc Length and Surface Area 345 . Arc Length . Surface Area 5.5 Projectile Motion 352 5.6 Applications of Integration to Physics and Engineering 361 CHAPTER 6 .. Exponentials, Logarithms and Other Transcendental Functions 375 6.1 The Natural Logarithm 375 . Logarithmic Differentiation 6.2 Inverse Functions 384 6.3 The Exponential Function 391 . Derivative of the Exponential Function 6.4 The Inverse Trigonometric Functions 399 6.5 The Calculus of the Inverse Trigonometric Functions 405 . Integrals Involving the Inverse Trigonometric Functions 6.6 The Hyperbolic Functions 411 . The Inverse Hyperbolic Functions . Derivation of the Catenary CHAPTER 7 .. Integration Techniques 421 7.1 Review of Formulas and Techniques 422 7.2 Integration by Parts 426 7.3 Trigonometric Techniques of Integration 433 . Integrals Involving Powers of Trigonometric Functions . Trigonometric Substitution 7.4 Integration of Rational Functions Using Partial Fractions 442 . Brief Summary of Integration Techniques 7.5 Integration Tables and Computer Algebra Systems 450 . Using Tables of Integrals . Integration Using a Computer Algebra System 7.6 Indeterminate Forms and LHopitals Rule 457 . Other Indeterminate Forms 7.7 Improper Integrals 467 . Improper Integrals with a Discontinuous Integrand . Improper Integrals with an Infinite Limit of Integration . A Comparison Test 7.8 Probability 479 CHAPTER 8 .. First-Order Differential Equations 491 8.1 Modeling with Differential Equations 491 . Growth and Decay Problems . Compound Interest 8.2 Separable Differential Equations 501 . Logistic Growth
  10. 10. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES Table of Contents ix 8.3 Direction Fields and Eulers Method 510 8.4 Systems of First-Order Differential Equations 521 . Predator-Prey Systems CHAPTER 9 .. Infinite Series 531 9.1 Sequences of Real Numbers 532 9.2 Infinite Series 544 9.3 The Integral Test and Comparison Tests 554 . Comparison Tests 9.4 Alternating Series 565 . Estimating the Sum of an Alternating Series 9.5 Absolute Convergence and the Ratio Test 571 . The Ratio Test . The Root Test . Summary of Convergence Tests 9.6 Power Series 579 9.7 Taylor Series 587 . Representation of Functions as Power Series . Proof of Taylors Theorem 9.8 Applications of Taylor Series 599 . The Binomial Series 9.9 Fourier Series 607 . Functions of Period Other Than 2 . Fourier Series and Music Synthesizers CHAPTER 10 .. Parametric Equations and Polar Coordinates 625 10.1 Plane Curves and Parametric Equations 625 10.2 Calculus and Parametric Equations 634 10.3 Arc Length and Surface Area in Parametric Equations 641 10.4 Polar Coordinates 649 10.5 Calculus and Polar Coordinates 660 10.6 Conic Sections 668 . Parabolas . Ellipses . Hyperbolas 10.7 Conic Sections in Polar Coordinates 677 CHAPTER 11 .. Vectors and the Geometry of Space 687 11.1 Vectors in the Plane 688 11.2 Vectors in Space 697 . Vectors in R3 11.3 The Dot Product 704 . Components and Projections
  11. 11. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES x Table of Contents 11.4 The Cross Product 714 11.5 Lines and Planes in Space 726 . Planes in R3 11.6 Surfaces in Space 734 . Cylindrical Surfaces . Quadric Surfaces . An Application CHAPTER 12 .. Vector-Valued Functions 749 12.1 Vector-Valued Functions 750 . Arc Length in R3 12.2 The Calculus of Vector-Valued Functions 758 12.3 Motion in Space 769 . Equations of Motion 12.4 Curvature 779 12.5 Tangent and Normal Vectors 786 . Tangential and Normal Components of Acceleration . Keplers Laws 12.6 Parametric Surfaces 799 CHAPTER 13 .. Functions of Several Variables and Partial Differentiation 809 13.1 Functions of Several Variables 809 13.2 Limits and Continuity 822 13.3 Partial Derivatives 833 13.4 Tangent Planes and Linear Approximations 844 . Increments and Differentials 13.5 The Chain Rule 854 . Implicit Differentiation 13.6 The Gradient and Directional Derivatives 864 13.7 Extrema of Functions of Several Variables 874 . Proof of the Second Derivatives Test 13.8 Constrained Optimization and Lagrange Multipliers 887 A M.F. Mood Standard Racket Greater Than 3THROAT THROAT Prince Racket FIRST STRING FIRST STRING Greater Than 4 Greater Than 5 Greater Than 6 COEFFICENT OF RESTITUTION RACKETS HELD BY VISE BALL VELOCITY OF 385 M PA FRAME BALL HITS FRAME IN THIS AREA 25 25 17 2627 32 45 40 44 32 74 77 43 45 50 42 42 47 44 55 55 55 52 52 52 53 53 52 41 34 2742 30 20 2634 25 35 35 35 32 45 27 28 30 40 45 45 47 66 65 22 45 24 27 CHAPTER 14 .. Multiple Integrals 901 14.1 Double Integrals 901 . Double Integrals over a Rectangle . Double Integrals over General Regions 14.2 Area, Volume and Center of Mass 916 . Moments and Center of Mass 14.3 Double Integrals in Polar Coordinates 926 14.4 Surface Area 933 14.5 Triple Integrals 938 . Mass and Center of Mass
  12. 12. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES Table of Contents xi 14.6 Cylindrical Coordinates 948 14.7 Spherical Coordinates 956 . Triple Integrals in Spherical Coordinates 14.8 Change of Variables in Multiple Integrals 962 CHAPTER 15 .. Vector Calculus 977 15.1 Vector Fields 977 15.2 Line Integrals 990 15.3 Independence of Path and Conservative Vector Fields 1003 15.4 Greens Theorem 1014 15.5 Curl and Divergence 1022 15.6 Surface Integrals 1032 . Parametric Representation of Surfaces 15.7 The Divergence Theorem 1044 15.8 Stokes Theorem 1053 15.9 Applications of Vector Calculus 1061 CHAPTER 16 .. Second-Order Differential Equations 1073 16.1 Second-Order Equations with Constant Coefficients 1074 16.2 Nonhomogeneous Equations: Undetermined Coefficients 1082 16.3 Applications of Second-Order Equations 1090 16.4 Power Series Solutions of Differential Equations 1098 Appendix A: Proofs of Selected Theorems A-1 Appendix B: Answers to Odd-Numbered Exercises A-13 Credits C-1 Index I-1 Bibliography See www.mhhe.com/Smithminton
  13. 13. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES McGraw-Hill Higher Education and Blackboard have teamed up. Blackboard, the Web-based course-management system, has partnered with McGraw- Hill to better allow students and faculty to use online materials and activities to complement face-to-face teaching. Blackboard features exciting social learning and teaching tools that foster more logical, visually impactful and active learning opportunities for students. Youll transform your closed-door classrooms into communities where students remain connected to their educational experience 24 hours a day. This partnership allows you and your students access to McGraw-Hills ConnectTM and CreateTM right from within your Blackboard courseall with one single sign-on. Not only do you get single sign-on with ConnectTM and CreateTM , you also get deep integration of McGraw-Hill content and content engines right in Blackboard. Whether youre choosing a book for your course or building ConnectTM assignments, all the tools you need are right where you want theminside of Blackboard. Gradebooks are now seamless. When a student completes an integrated ConnectTM as- signment, the grade for that assignment automatically (and instantly) feeds your Blackboard grade center. McGraw-Hill and Blackboard can now offer you easy access to industry leading tech- nology and content, whether your campus hosts it, or we do. Be sure to ask your local McGraw-Hill representative for details. xii
  14. 14. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES Seeing the Beauty and Power of Mathematics The calculus course is a critical course for science, technology, engineering, and math majors. This course sets the stage for many majors and is where students see the beauty of mathematics, encouraging them to take upper-level math courses. In a calculus market-research study conducted in 2008, calculus faculty pointed out three critical components to student success in the calculus. The most critical is mastery of the prerequisite algebra and trigonometry skills. Our market research study showed that 58 percent of faculty mentioned that students struggled withcalculusbecauseofpooralgebraskillsand72percentsaidbecauseofpoortrigonometry skills. This is the number one learning challenge preventing students from being successful in the rst calculus course. The second critical component for student success is a text that presents calculus concepts, especially the most challenging concepts, in a clear and elegant manner. This helps students see and appreciate the beauty and power of mathematics. Lastly, calculus faculty told us that it is critical for a calculus text to include all the classic calculus problems. Other calculus textbooks may reect one or two of these critical components. However, there is only ONE calculus textbook that includes all three: Smith/Minton, 4e. Read on to understand how Smith/Minton handles all three issues, helping your students to see the beauty and power of mathematics. Mastery of Prerequisite Algebra and Trigonometry Skills ALEKS Prep for Calculus is a Web-based program that focuses on prerequisite and introductory material for Calculus, and can be used during the rst six weeks of the term to prepare students for success in the course. ALEKS uses articial intelligence and adaptive questioning to assess precisely a students preparedness and provide personalized instruction on the exact topics the student is most ready to learn. By providing comprehensive explanations, practice and feedback, ALEKS allows students to quickly ll in gaps in prerequisite knowledge on their own time, while also allowing instructors to focus on core course concepts. Use ALEKS Prep for Calculus during the rst six weeks of the term to see improved student condence and performance, as well as fewer drops. xiii
  15. 15. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES xiv Seeing the Beauty and Power of Mathematics ALEKS PREP FOR CALCULUS FEATURES: r Articial Intelligence: Targets Gaps in Individual Student Knowledge r Adaptive, Open-Response Environment: Avoids Multiple-Choice Questions and Ensures Student Mastery r Automated Reports: Monitor Student and Class Progress For more information about ALEKS, please visit: www.aleks.com/highered/math ALEKS is a registered trademark of ALEKS Corporation. Elegant Presentation of Calculus Concepts Calculus reviewers and focus groups worked with the authors to provide a more concise, streamlined presentation that maintains the clarity of past editions. New examples and exercises illustrate the physical meaning of the derivative and give real counterexamples. The proofs of basic differentiation rules in sections 2.42.6 have been revised, making them more elegant and easy for students to follow, as were the theorems and proofs of basic integration and integration rules. Further, an extensive revision of multivariable calculus chapters includes a revision of the denition and proof of the derivative of a vector-valued function, the normal vector, the gradiant and both path and surface integration. More than any other text, I believe Smith/Minton approaches deep concepts from a thoughtful perspective in a very friendly style.Louis Rossi, University of Delaware [Smith-Minton is] sufciently rigorous without being considered to too mathy. It is a very readable book with excellent graphics and outstanding applications sections.Todd King, Michigan Technological University Rigorous, more interesting to read than Stewart. Full of great application examples.Fred Bourgoin, Laney College The material is very well presented in a rigorous manner . . . very readable, numerous examples for students with a wide variety of interests.John Heublein, Kansas State UniversitySalina
  16. 16. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES Seeing the Beauty and Power of Mathematics xv Classic Calculus Problems Many new classic calculus exercises have been added. From basic derivative problems to related rates applications involving ow, and multivariable applications to electricity and magnetism, these exercises give students the opportunity to challenge themselves and allow instructors exibility when choosing assignments. The authors have also reorganized the exercises to move consistently from the simplest to most difcult problems, making it easier for instructors to choose exercises of the appropriate level for their students. They moved the applications to a separate section within the exercise sets and were careful to include many examples from the common calculus majors such as engineering, physical sciences, computer science and biology. Thought provoking, clearly organized, challenging, excellent problem sets, guarantee that students will actually read the book and ask questions about concepts and topics. Donna Latham, Sierra College [Smith-Minton is] a traditional calculus book that is easy to read and has excellent applications.Hong Liu, Embry-Riddle Aeronautical UniversityDaytona Beach The rigorous treatment of calculus with an easy conversational style that has a wealth of examples and problems. The topics are nicely arranged so that theoretical topics are segregated from applications.Jayakumar Ramanatan, Eastern Michigan University
  17. 17. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGESxvi
  18. 18. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGESxvii
  19. 19. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES the future of custom publishing is here. Introducing McGraw-Hill Createa new, self- service website that allows you to create custom course materials by drawing upon McGraw-Hills comprehensive, cross-disciplinary content and other third party resources. Select, then arrange the content in a way that makes the most sense for your course. Even personalize your book with your course information and choose the best format for your studentscolor print, black-and-white print, or eBook. Build custom print and eBooks easily Combine material from dierent sources and even upload your own content Receive a PDF review copy in minutes begin creating now: www.mcgrawhillcreate.com Start by registering for a free Create account. If you already have a McGraw-Hill account with one of our other products, you will not need to register on Create. Simply Sign In and enter your username and password to begin using the site. ws you to create custom ing upon McGraw-Hills ciplinary content and other ect, then arrange the content most sense for your course. ok with your course the best format for your ck-and-white print, or eBook. nd eBooks easily om dierent sources ur own content w copy in minutes If you already have a McGraw-Hill account with one of our other products, you will not need to register on Create. Simply Sign In and enter your username and password to begin using the site. xviii
  20. 20. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES edit, share and approve like never before. After you've completed your project, simply go to the My Projects tab at the top right corner of the page to access and manage all of your McGraw-Hill Create projects. Here you will be able to edit your projects and share them with colleagues. An ISBN will be assigned once your review copy has been ordered. Click Approve to make your eBook available for student purchase or print book available for your school or bookstore to order. At any time you can modify your projects and are free to create as many projects as needed. receive your pdf review copy in minutes! Request an eBook review copy and receive a free PDF sample in minutes! Print review copies are also available and arrive in just a few days. Finallya way to quickly and easily create the course materials youve always wanted. Imagine that. questions? Please visit www.mcgrawhillcreate.com/createhelp for more information. what youve only imagined. My Projects tab at th to access and manag projects. Here you w and share them with assigned once your Click Approve to ma student purchase or school or bookstore modify your projects projects as needed. xix
  21. 21. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES xx Seeing the Beauty and Power of Mathematics SUPPLEMENTS ONLINE INSTRUCTORS SOLUTIONS MANUAL An invaluable, timesaving resource, the Instructors Solutions Manual contains comprehen- sive, worked-out solutions to the odd- and even-numbered exercises in the text. STUDENT SOLUTIONS MANUAL (ISBN 978-0-07-7256968) The Student Solutions Manual is a helpful reference that contains comprehensive, worked- out solutions to the odd-numbered exercises in the text. ONLINE TESTBANK AND PREFORMATTED TESTS Brownstone Diploma testing software offers instructors a quick and easy way to cre- ate customized exams and view student results. Instructors may use the software to sort questions by section, difculty level, and type; add questions and edit existing questions; create multiple versions of questions using algorithmically-randomized variables; prepare multiple-choice quizzes; and construct a grade book. ONLINE CALCULUS CONCEPTS VIDEOS Students will see essential concepts explained and brought to life through dynamic ani- mations in this new video series available on DVD and on the Smith/Minton website. The twenty-ve key concepts, chosen after consultation with calculus instructors across the country, are the most commonly taught topics that students need help with and that also lend themselves most readily to on-camera demonstration. CALCULUS AND TECHNOLOGY It is our conviction that graphing calculators and computer algebra systems must not be used indiscriminately. The focus must always remain on the calculus. We have en- sured that each of our exercise sets offers an extensive array of problems that should be worked by hand. We also believe, however, that calculus study supplemented with an intelligent use of technology gives students an extremely powerful arsenal of problem- solving skills. Many passages in the text provide guidance on how to judiciously use and not abusegraphing calculators and computers. We also provide ample opportunity for students to practice using these tools. Exercises that are most easily solved with the aid of a graphing calculator or a computer algebra system are easily identied with a icon. IMPROVEMENTS IN THE FOURTH EDITION Building upon the success of the Third Edition of Calculus, we have made the following revisions to produce an even better Fourth Edition: Presentation r A key goal of the Fourth Edition revision was to offer a clearer presentation of calculus. With this goal in mind, the authors were able to reduce the amount of material by nearly 150 pages. r The level of rigor has been carefully balanced to ensure that concepts are presented in a rigorously correct manner without allowing technical details to overwhelm beginning calculus students. For example, the sections on continuity, sum rule, chain rule, the denite integral and Riemann sums, introductory vectors, and advanced multivariable calculus (including the Greens Theorem section) have been revised to improve the theorems, denitions, and/or proofs. r The exercise sets were redesigned in an effort to aid instructors by allowing them to more easily identify and assign problems of a certain type. r The derivatives of hyperbolic functions are developed in Section 6.6, giving this important class of functions a full development. Separating these functions from the
  22. 22. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES Seeing the Beauty and Power of Mathematics xxi exponential and trigonometric functions allows for early and comprehensive exploration of the relationship between these functions, exponential functions, trigonometric functions, and their derivatives and integrals. Exercises r More than 1,000 new classic calculus problems were added, covering topics from polynomials to multivariable calculus, including optimization, related rates, integration techniques and applications, parametric and polar equations, vectors, vector calculus, and differential equations. r A reorganization of the exercise sets makes the range of available exercises more transparent. Earlier exercises focus on fundamentals, as developed in examples in the text. Later exercises explore interesting extensions of the material presented in the text. r Multi-step exercises help students make connections among concepts and require students to become more critical readers. Closely related exercises are different parts of the same numbered exercise, with follow-up questions to solidify lessons learned. r Application exercises have been separated out in all appropriate sections. A new header identies the location of applied exercises which are designed to show students the connection between what they learn in class, other areas of study, and outside life. This differentiates the applications from exploratory exercises that allow students to discover connections and extensions for themselves. ACKNOWLEDGMENTS A project of this magnitude requires the collaboration of an incredible number of talented and dedicated individuals. Our editorial staff worked tirelessly to provide us with countless surveys, focus group reports, and reviews, giving us the best possible read on the current state of calculus instruction. First and foremost, we want to express our appreciation to our sponsoring editor John Osgood and our developmental editor Eve Lipton for their encouragement and support to keep us on track throughout this project. They challenged us to make this a better book. We also wish to thank our editorial director Stewart Mattson, and director of development Kris Tibbets for their ongoing strong support. We are indebted to the McGraw-Hill production team, especially project manager Peggy Selle and design coordinator Laurie Janssen, for (among other things) producing a beautifullydesignedtext.TheteamatMRCChasprovideduswithnumeroussuggestionsfor clarifying and improving the exercise sets and ensuring the texts accuracy. Our marketing manager Kevin Ernzen has been instrumental in helping to convey the story of this book to a wider audience, and media project manager Sandy Schnee created an innovative suite of media supplements. Our work on this project beneted tremendously from the insightful comments we received from many reviewers, survey respondents and symposium attendees. We wish to thank the following individuals whose contributions helped to shape this book: REVIEWERS OF THE FOURTH EDITION Andre Adler, Illinois Institute of Technology Daniel Balaguy, Sierra College Frank Bauerle, University of California Santa Cruz Fred Bourgoin, Laney College Kris Chatas, Washtenaw Community College Raymond Clapsadle, University of Memphis Dan Edidin, University of Missouri Columbia Timothy Flaherty, Carnegie Mellon University Gerald Greivel, Colorado School of Mines Jerrold Grossman, Oakland University Murli Gupta, George Washington University Ali Hajjafar, University of Akron
  23. 23. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES xxii Seeing the Beauty and Power of Mathematics Donald Hartig, California Polytechnic State UniversitySan Luis Obispo John Heublein, Kansas State UniversitySalina Joseph Kazimir, East Los Angeles College Harihar Khanal, Embry-Riddle Aeronautical UniversityDaytona Beach Todd King, Michigan Technological University Donna Latham, Sierra College Rick Leborne, Tennessee Technological University Hong Liu, Embry-Riddle Aeronautical UniversityDaytona Beach Paul Loya, Binghamton University Laurie Pieracci, Sierra College Michael Price, University of Oregon Michael Quail, Washtenaw Community College Jayakumar Ramanatan, Eastern Michigan University Louis Rossi, University of Delaware Mohammad Saleem, San Jose State University Angela Sharp, University of MinnesotaDuluth Greg Spradlin, Embry-Riddle Aeronautical UniversityDaytona Beach Kelly Stady, Cuyahoga Community College Richard Swanson, Montana State UniversityBozeman Fereja Tahir, Illinois Central College Marie Vitulli, University of Oregon Patrick Ward, Illinois Central College Jay Zimmerman, Towson University WITH MANY THANKS TO OUR PREVIOUS REVIEWER PANEL: Kent Aeschliman, Oakland Community College Stephen Agard, University of Minnesota Charles Akemann, University of California, Santa Barbara Tuncay Aktosun, University of Texas Arlington Gerardo Aladro, Florida International University Dennis Bila, Washtenaw Community College Ron Blei, University of Connecticut Joseph Borzellino, California Polytechnic State University Timmy Bremer, Broome Community College Qingying Bu, University of Mississippi Katherine Byler, California State University Fresno Roxanne Byrne, University of Colorado Denver Fengxin Chen, University of Texas at San Antonio Youn-Min Chou, University of Texas at San Antonio Leo G. Chouinard, University of Nebraska Lincoln Si Kit Chung, The University of Hong Kong Donald Cole, University of Mississippi David Collingwood, University of Washington Tristan Denley, University of Mississippi Judith Downey, University of NebraskaOmaha Linda Duchrow, Regis University Jin Feng, University of Massachusetts, Amherst Carl FitzGerald, University of California, San Diego Mihail Frumosu, Boston University John Gilbert, University of Texas Rajiv Gupta, University of British Columbia Guershon Harel, University of California, San Diego Richard Hobbs, Mission College Shun-Chieh Hsieh, Chang Jung Christian University Josena Barnachea Janier, University Teknologi Petronas Jakub Jasinski, University of Scranton George W. Johnson, University of South Carolina Nassereldeen Ahmed Kabbashi, International Islamic University G. P. Kapoor, Indian Institute of Technology Kanpur Jacob Kogan, University of Maryland, Baltimore Carole King Krueger, University of Texas at Arlington Kenneth Kutler, Brigham Young University Hong-Jian Lai, West Virginia University John Lawlor, University of Vermont Richard Le Borne, Tennessee Technological University Glenn Ledder, University of NebraskaLincoln Sungwook Lee, University of Southern Mississippi Mary Legner, Riverside Community College Steffen Lempp, University of Wisconsin Madison Barbara MacCluer, University of Virginia William Margulies, California State University, Long Beach Mary B. Martin, Middle Tennessee State University Mike Martin, Johnson Community College James Meek, University of Arkansas Carrie Muir, University of Colorado Michael M. Neumann, Mississippi State University Sam Obeid, University of North Texas Iuliana Oprea, Colorado State University Anthony Peressini, University of Illinois Greg Perkins, Hartnell College
  24. 24. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES Seeing the Beauty and Power of Mathematics xxiii Tan Ban Pin, National University of Singapore Linda Powers, Virginia Polytechnic Institute and State University Mohammad A. Rammaha, University of NebraskaLincoln Richard Rebarber, University of Nebraska Lincoln Kim Rescorla, Eastern Michigan University Edgar Reyes, Southeastern Louisiana University Mark Smith, University of Illinois Donald Solomon, University of WisconsinMilwaukee Rustem Suncheleev, Universiti Putra Malaysia Anthony Thomas, University of WisconsinPlatteville Anthony Vance, Austin Community College P. Veeramani, Indian Institute of Technology Madras Anke Walz, Kutztown University of Pennsylvania Scott Wilde, Baylor University James Wilson, Iowa State University Raymond Wong, University of California, Santa Barbara Bernardine R. Wong Cheng Kiat, University of Malaya Teri Woodington, Colorado School of Mines Gordon Woodward, University of NebraskaLincoln Haidong Wu, University of Mississippi Adil Yaqub, University of California, Santa Barbara Hong-Ming Yin, Washington State University, Pullman Paul Yun, El Camino College Jennifer Zhao, University of Michigan at Dearborn In addition, a number of our colleagues graciously gave their time and energy to help create or improve portions of the manuscript. We would especially like to thank Richard Grant, Bill Ergle, Jack Steehler, Ben Huddle, Chris Lee, Dave Taylor, Dan Larsen and Jan Minton of Roanoke College for sharing their expertise in calculus and related applications; student assistants Danielle Shiley and Hannah Green for their insight and hard work; Tim Pennings and Art Benjamin for inspirations both mathematical and personal; Tom Burns for help with an industrial application; Gregory Minton and James Albrecht for suggesting several brilliant problems; Dorothee Blum of Millersville University for helping to class-test an early version of the manuscript; Bruce Ikenaga of Millersville University for generously sharing his expertise in TeX and Corel Draw and Pam Vercellone-Smith, for lending us her expertise in many of the biological applications. We also wish to thank Dorothee Blum, Bob Buchanan, Antonia Cardwell, Roxana Costinescu, Chuck Denlinger, Bruce Ikenaga, Zhoude Shao, Ron Umble and Zenaida Uy of Millersville University for offering numerous helpful suggestions for improvement. In addition, we would like to thank all of our students throughout the years, who have (sometimes unknowingly) eld-tested innumerable ideas, some of which worked and the rest of which will not be found in this book. Ultimately, this book is for our families. We simply could not have written a book of this magnitude without their strong support. We thank them for their love and inspiration throughout our growth as textbook authors. Their understanding, in both the technical and the personal sense, was essential. They provide us with the reason why we do all of the things we do. So, it is tting that we especially thank our wives, Pam Vercellone-Smith and Jan Minton and our children, Katie and Michael Smith and Kelly and Greg Minton; and our parents, George and Anne Smith and Paul and Mary Frances Minton. Robert T. Smith Lancaster, Pennsylvania Roland B. Minton Salem, Virginia
  25. 25. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES Applications Index Biology Alligator sex, 77 Anthills, 344 Bacterial growth, 491492, 499 Biological oscillations, 668 Bird ight, 246 Birth rates, 283 Cell age, 484 Cell division, 398 Circulatory system, 232 Competitive exclusion principle, 526 Coyote, 358 Cricket chirping, 20 Decay, 491496 Dinosaurs, 491 Dog swimming, 886 E. coli growth, 499 Firey ashes, 203 Fish population, 509 Fish speed, 246 Fossils, 491 Genetics, 886 Growth, 491496 Height of person, 485 Human speed, 117 Kangaroo legs, 315 Leg width and body weight, 134 Paleontology, 491 Pollutant density, 947 Pollution, 169 Predator-prey system, 293, 527 Pupil dilation, 47, 246 Pupil size, 84, 466 Reproductive rate, 184 Shark prey tracking, 873 Spruce budworm, 184, 222 Tree infestation, 520 Zebra stripes, 520 Chemistry Acid-base titration, 383 Autocatalytic reaction, 242243 Bimolecular reactions, 509 Concentration analysis, 396, 397 Methane, 713 Product, 246 Rate of reaction, 242243 Reactants, 246 Second-order chemical reaction, 246 Temperature, entropy, and Gibbs free energy, 843 Construction Building height, 237 Sand pile height, 238 Sliding ladder, 234 Demographics Birthrate, 323 Critical threshold, 512513 Maximum sustainable population, 506 Population and time, 20 Population carrying capacity, 505 Population estimation, 920 Population growth maximum, 244 Population prediction, 12 Rumor spread, 398 Urban population growth, 126 Economics Advertising costs, 211, 238 Airline ticket sales, 35 Annual percentage yield, 496 Asset depreciation, 497498 Bank account balance, 210 Barge costs, 246 Capital expenditure, 863 Complementary commodities, 843 Compound interest, 496498, 499 Consumer surplus, 291 Cost minimization, 229230, 231 Coupon collectors problem, 564 Demand, 244 Diminishing returns, 233 Economic Order Quantity, 283, 291 Elasticity of demand, 241242, 244 Endowment, 508 Future value, 501 Gini index, 272 Gross domestic product, 265, 272 Ice cream sales, 713 Income calculation, 862 Income stream, 500 Income tax, 68, 127 Initial investment, 508 Investing, 210 Investment strategies, 506 Investment value, 843 Just-in-time inventory, 251, 291 Manufacturing costs, 211 Marginal cost, 239 Marginal prot, 239 Mortgages, 508 Multiplier effect, 553 National debt, 135 Oil consumption, 323 Oil prices, 925 Packing, 544 Parking fees, 57 Present value, 500, 553 Product sales, 202 Production costs, 238, 240241, 324 Production optimization, 891892 Prot maximization, 324 Rate of change, 236, 239244 Relative change in demand, 240241 Relative change in price, 240 Resale value, 509 Retirement fund, 508 Revenue, 139 Revenue maximization, 233 Rule of 72, 501 Salary increase, 77, 391 Stock investing, 873 Substitute commodities, 843 Supply and demand, 323 Tax rates, 500 Tax tables, 73 xxiv
  26. 26. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES Applications Index xxv Unit price, 141 Worker productivity, 211 Engineering Airplane design, 227 Beam sag, 851 Capacitors, 1090 Car design, 977 Catenary, 411 Ceiling shape, 676 Circuit charge, 1091 Circuitry, 35, 1096 Cooling towers, 745 Electric dipole, 586 Falling ladder, 646 Flashlight design, 670 Highway construction costs, 229230, 231 Hydrostatic force on dam, 368 International Space Station, 375 Light pole height, 35 Metal sheet gauge, 851 Norman window, 232 Oil pipeline, 231 Oil rig beam, 713 Oil tank capacity, 404 Parabolic dish, 741, 742 Pyramids, 335 Reliability testing, 421 RoboCup, 749 Robot vision, 239 Rocket fuel, 369 Rocket height, 86 Rocket launch, 35 Rocket thrust, 890 Saddle Dome, 744 Screen door closing, 1081 Series circuit, 1096 Soda can design, 227228 Spacecraft launch, 238 Spiral staircase, 758 St. Louis Gateway Arch, 411, 418 Telegraph cable, 383 Thrust-time curve, 370 Tower height, 3334 Useful life phase, 421 Voltage, 10911092 Water ow, 323 Water pumping, 239, 363 Water reservoir, 211 Water system, 117 Water tank, 288, 290 Water tower, 369 Environment Oil spill, 234, 237 Hobbies Jewelry making, 344 Photography, 20 Home Garden construction, 223224 Medicine Achilles tendon, 315 Allosteric enzyme, 142 Antibiotics, 500 Antidepressants, 500 Brain neurons, 398 Computed tomography, 327 Drug concentration, 398 Drug dosage, 553 Drug half-life, 500 Drug injection, 86 Drug sensitivity, 246 Enzymatic reaction, 194 Foot arch, 322 Glucose concentration, 1097 HIV, 283 Infection, 237 Pneumotachograph, 310 Tendon force, 322 Music Digital, 531 Guitar string, 238, 843 Octaves, 8 Piano tuning, 35, 619 Synthesizers, 617618 Timbre, 617 Tuning, 8 Physics AC circuit, 232, 293 Acceleration, 135 Air resistance, 356 Atmospheric pressure, 398 Ball motion, 353 Black body radiation, 606 Boiling point of water at elevation, 20 Change in position, 277 Distance fallen, 288 Electric potential, 607 Electromagnetic eld, 511 Electromagnetic radiation, 606 Falling object position, 257 Falling object velocity, 418 Freezing point, 117 Frequency modulation, 222 Friction, 77 Gas laws, 238 Gravitation, 184 Half-life, 499 Hydrostatic forces, 371 Hyperbolic mirrors, 674 Impulse-momentum equation, 283 Light path, 211, 231 Light reection, 232 Newtons Law of Cooling, 494, 499 Object distance fallen, 6 Object launch, 358 Object velocity, 310 Pendulum, 1097 Plancks law, 398, 606 Planetary orbits, 640 Projectiles, 265 Radio waves, 2728 Radioactive decay, 494 Raindrop evaporation, 237 Relativity, 86, 184 Rod density, 243244 Solar and Heliospheric Observatory, 173 Sound waves, 632 Spring motion, 154, 1081 Spring-mass system, 142 Terminal velocity, 509 Thrown ball, 231 Velocity, 57 Velocity required to reach height, 354 Voltage, 293 Volume and pressure, 157 Weightlessness, 360 Sports/ Entertainment Auto racing, 687 Badminton, 283 Ball height, 233 Baseball bat corking, 371 Baseball bat hit, 238, 321 Baseball bat mass, 366 Baseball bat sweet spot, 367 Baseball batting average, 863 Baseball impulse, 365 Baseball knuckleball, 57 Baseball outelding, 404 Baseball pitching, 57, 359 Baseball player gaze, 406407 Baseball spin, 724 Baseball statistics analysis, 8 Baseball velocity, 383 Basketball free throws, 359, 486 Basketball perfect swish, 86 Bicycling, 20, 553
  27. 27. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-FM-MAIN MHDQ256-Smith-v1.cls January 8, 2011 12:17 LT (Late Transcendental) CONFIRMING PAGES xxvi Applications Index Catch, 369 Circus act, 359, 634 Coin toss, 479, 564 Computer game plays, 20 Curveball, 725 Diver velocity, 352, 358 Equipment design, 901 Football kick, 410 Football points scored, 885 Football punt, 778 Football spiral pass, 725 Goal probability, 486 Golf ball aim, 404 Golf ball distance, 809 Golf ball motion, 972 Golf ball on moon, 360 Golf ball spin, 20 Golf club impact, 141 Golf hook shot, 725 Golf put, 655 Golf shot analysis, 140 High jumping, 315 Hockey shot, 410 Home run, 778 Juggling, 360 Jumping, 358 Kayaking, 696 Keno, 486 Knuckleball, 357, 466 Marathon, 107 Merry-go-round, 775 Mountaineering, 873 Movie theater design, 404 Olympic Games, 676 Racetrack design, 713 Record player, 35 Roller coaster, 194, 778 Rugby ball, 344 Sailing, 895 Scrambler ride, 637, 641 Skateboarding, 360 Skiing, 410, 644, 901 Skydiving, 132133, 418, 466, 694, 696 Soccer goal probability, 398 Soccer kick, 359 Stadium design, 798 Stadium wave, 798 Tennis ball energy lost, 320 Tennis ball work done, 369 Tennis game win, 553 Tennis matches, 194 Tennis serve, 355, 778 Tennis serve error margin, 126 Tennis serve speed, 873 Tennis slice serve, 725 Tie probability, 203 Torque, 722 Track construction, 233 Trading cards, 500 Weightlifting, 362 Travel Aircraft steering, 694 Airline ticket sales, 35 Airplane engine thrust, 696, 704 Car engine force, 369 Car speed, 291 Car velocity, 265 Car weight, 713 Commuting, 246 Crash test, 370 Distance from airport, 237 Fuel efciency, 126, 142 Gas costs, 884 Gas mileage, 126, 863 Jet speed, 633 Jet tracking, 236 Plane altitude, 135 Speed of sound, 625 Speed trap, 235 Stopped car, 77 Walking, 571
  28. 28. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES C H A P T E R 0 Preliminaries In this chapter, we present a collection of familiar topics, primarily those that we consider essential for the study of calculus. While we do not intend this chapter to be a comprehensive review of precalculus math- ematics, we have tried to hit the highlights and provide you with some standard notation and language that we will use throughout the text. As it grows, a chambered nautilus creates a spiral shell. Behind this beautiful geometry is a surprising amount of mathematics. The nautilus grows in such a way that the overall proportions of its shell remain constant. That is, if you draw a rectangle to circumscribe the shell, the ratio of height to width of the rectangle remains nearly constant. There are several ways to represent this property mathematically. In polar coordinates (which we present in Chapter 10), we study logarith- mic spirals that have the property that the angle of growth is constant, corresponding to the constant proportions of a nautilus shell. Using basic geometry, you can divide the circumscribing rectangle into a sequence of squares as in the gure. The relative sizes of the squares form the famous Fibonacci sequence 1, 1, 2, 3, 5, 8, . . . , where each number in the sequence is the sum of the preceding two numbers. 21 13 8 5 32 A nautilus shell The Fibonacci sequence has an amazing list of interesting properties. (Search on the Internet to see what we mean!) Numbers in the sequence have a surprising habit of showing up in nature, such as the number of petals on a lily (3), buttercup (5), marigold (13), black-eyed Susan (21) and pyrethrum (34). Although we have a very simple description of how to generate the Fibonacci sequence, think about howyoumightdescribeitasafunction.Aplot of the rst several numbers in the sequence (shown in Figure 0.1) should give you the impression of a graph curving up, perhaps a parabola or an exponential curve. Two aspects of this problem are impor- tant themes throughout the calculus. One of these is the importance of looking for pat- terns to help us better describe the world. A second theme is the interplay between graphs and functions. By connecting the techniques of algebra with the visual images provided by graphs, you will signicantly improve your ability to solve real-world problems mathematically. 1
  29. 29. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 2 CHAPTER 0 .. Preliminaries 0-2 1 2 3 4 5 6 7 8 x y 5 10 15 20 25 30 35 0 FIGURE 0.1 The Fibonacci sequence 0.1 THE REAL NUMBERS AND THE CARTESIAN PLANE The Real Number System and Inequalities Our journey into calculus begins with the real number system, focusing on those properties that are of particular interest for calculus. The set of integers consists of the whole numbers and their additive inverses: 0, 1, 2, 3, . . . . A rational number is any number of the form p q , where p and q are integers and q = 0. For example, 2 3 , 7 3 and 27 125 are all rational numbers. Notice that every integer n is also a rational number, since we can write it as the quotient of two integers: n = n 1 . The irrational numbers are all those real numbers that cannot be written in the form p q , where p and q are integers. Recall that rational numbers have decimal expansions that either terminate or repeat. For instance, 1 2 = 0.5, 1 3 = 0.33333, 1 8 = 0.125 and 1 6 = 0.166666 are all rational numbers. By contrast, irrational numbers have decimal expansions that do not repeat or terminate. For instance, three familiar irrational numbers and their decimal expansions are 2 = 1.41421 35623 . . . , = 3.14159 26535 . . . and e = 2.71828 18284 . . . . We picture the real numbers arranged along the number line displayed in Figure 0.2 (the real line). The set of real numbers is denoted by the symbol R. 0 5432112345 2 3 p e FIGURE 0.2 The real line For real numbers a and b, where a < b, we dene the closed interval [a, b] to be the set of numbers between a and b, including a and b (the endpoints). That is, [a, b] = {x R | a x b}, as illustrated in Figure 0.3, where the solid circles indicate that a and b are included in [a, b]. a b FIGURE 0.3 A closed interval
  30. 30. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 0-3 SECTION 0.1 .. The Real Numbers and the Cartesian Plane 3 Similarly, the open interval (a, b) is the set of numbers between a and b, but not including the endpoints a and b, that is, (a, b) = {x R | a < x < b}, as illustrated in Figure 0.4, where the open circles indicate that a and b are not included in (a, b). Similarly, we denote the set {x R | x > a} by the interval notation (a, ) and {x R | x < a} by (, a). In both of these cases, it is important to recognize that and are not real numbers and we are using this notation as a convenience. a b FIGURE 0.4 An open interval You should already be very familiar with the following properties of real numbers. THEOREM 1.1 If a and b are real numbers and a < b, then (i) For any real number c, a + c < b + c. (ii) For real numbers c and d, if c < d, then a + c < b + d. (iii) For any real number c > 0, a c < b c. (iv) For any real number c < 0, a c > b c. REMARK 1.1 We need the properties given in Theorem 1.1 to solve inequalities. Notice that (i) says that you can add the same quantity to both sides of an inequality. Part (iii) says that you can multiply both sides of an inequality by a positive number. Finally, (iv) says that if you multiply both sides of an inequality by a negative number, the inequality is reversed. We illustrate the use of Theorem 1.1 by solving a simple inequality. EXAMPLE 1.1 Solving a Linear Inequality Solve the linear inequality 2x + 5 < 13. Solution We can use the properties in Theorem 1.1 to solve for x. Subtracting 5 from both sides, we obtain (2x + 5) 5 < 13 5 or 2x < 8. Dividing both sides by 2, we obtain x < 4. We often write the solution of an inequality in interval notation. In this case, we get the interval (, 4). You can deal with more complicated inequalities in the same way. EXAMPLE 1.2 Solving a Two-Sided Inequality Solve the two-sided inequality 6 < 1 3x 10. Solution First, recognize that this problem requires that we nd values of x such that 6 < 1 3x and 1 3x 10. It is most efcient to work with both inequalities simultaneously. First, subtract 1 from each term, to get 6 1 < (1 3x) 1 10 1 or 5 < 3x 9.
  31. 31. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 4 CHAPTER 0 .. Preliminaries 0-4 Now, divide by 3, but be careful. Since 3 < 0, the inequalities are reversed. We have 5 3 > 3x 3 9 3 or 5 3 > x 3. We usually write this as 3 x < 5 3 , or in interval notation as [3, 5 3 ). y 4224 8 4 4 8 x 1 FIGURE 0.5 y = x 1 x + 2 You will often need to solve inequalities involving fractions. We present a typical example in the following. EXAMPLE 1.3 Solving an Inequality Involving a Fraction Solve the inequality x 1 x + 2 0. Solution In Figure 0.5, we show a graph of the function, which appears to indicate that the solution includes all x < 2 and x 1. Carefully read the inequality and observe that there are only three ways to satisfy this: either both numerator and denominator are positive, both are negative or the numerator is zero. To visualize this, we draw number lines for each of the individual terms, indicating where each is positive, negative or zero and use these to draw a third number line indicating the value of the quotient, as shown in the margin. In the third number line, we have placed an above the 2 to indicate that the quotient is undened at x = 2. From this last number line, you can see that the quotient is nonnegative whenever x < 2 or x 1. We write the solution in interval notation as (, 2) [1, ). Note that this solution is consistent with what we see in Figure 0.5. For inequalities involving a polynomial of degree 2 or higher, factoring the polynomial and determining where the individual factors are positive and negative, as in example 1.4, will lead to a solution. EXAMPLE 1.4 Solving a Quadratic Inequality Solve the quadratic inequality x2 + x 6 > 0. (1.1) Solution In Figure 0.6, we show a graph of the polynomial on the left side of the inequality. Since this polynomial factors, (1.1) is equivalent to (x + 3)(x 2) > 0. (1.2) This can happen in only two ways: when both factors are positive or when both factors are negative. As in example 1.3, we draw number lines for both of the individual factors, indicating where each is positive, negative or zero and use these to draw a number line representing the product. We show these in the margin. Notice that the third number line indicates that the product is positive whenever x < 3 or x > 2. We write this in interval notation as (, 3) (2, ). x 1 x 21 0 2 x 1 1 0 x 2 2 0 y x 10 10 20 62 4246 FIGURE 0.6 y = x2 + x 6 (x 3)(x 2) 2 00 3 x 2 2 0 x 3 3 0 No doubt, you will recall the following standard denition. DEFINITION 1.1 The absolute value of a real number x is |x| = x, if x 0. x, if x < 0
  32. 32. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 0-5 SECTION 0.1 .. The Real Numbers and the Cartesian Plane 5 Make certain that you read Denition 1.1 correctly. If x is negative, then x is positive. This says that |x| 0 for all real numbers x. For instance, using the denition, |4| = (4) = 4. Notice that for any real numbers a and b, |a b| = |a| |b|, although |a + b| = |a| + |b|, in general. (To verify this, simply take a = 5 and b = 2 and compute both quantities.) However, it is always true that |a + b| |a| + |b|. NOTES For any two real numbers a and b, |a b| gives the distance between a and b. (See Figure 0.7.) This is referred to as the triangle inequality. The interpretation of |a b| as the distance between a and b (see the note in the margin) is particularly useful for solving inequalities involving absolute values. Wherever possible, we suggest that you use this interpretation to read what the inequality means, rather than merely following a procedure to produce a solution. a b a b FIGURE 0.7 The distance between a and b EXAMPLE 1.5 Solving an Inequality Containing an Absolute Value Solve the inequality |x 2| < 5. (1.3) Solution First, take a few moments to read what this inequality says. Since |x 2| gives the distance from x to 2, (1.3) says that the distance from x to 2 must be less than 5. So, nd all numbers x whose distance from 2 is less than 5. We indicate the set of all numbers within a distance 5 of 2 in Figure 0.8. You can now read the solution directly from the gure: 3 < x < 7 or in interval notation: (3, 7). 2 5 3 2 5 72 5 5 FIGURE 0.8 |x 2| < 5 Many inequalities involving absolute values can be solved simply by reading the in- equality correctly, as in example 1.6. EXAMPLE 1.6 Solving an Inequality with a Sum Inside an Absolute Value Solve the inequality |x + 4| 7. (1.4) Solution To use our distance interpretation, we must rst rewrite (1.4) as |x (4)| 7. This now says that the distance from x to 4 is less than or equal to 7. We illustrate the solution in Figure 0.9, from which it follows that the solution is 11 x 3 or [11, 3]. 4 7 11 4 7 34 7 7 FIGURE 0.9 |x + 4| 7 Recall that for any real number r > 0, |x| < r is equivalent to the following inequality not involving absolute values: r < x < r. In example 1.7, we use this to revisit the inequality from example 1.5. EXAMPLE 1.7 An Alternative Method for Solving Inequalities Solve the inequality |x 2| < 5. Solution This is equivalent to the two-sided inequality 5 < x 2 < 5. Adding 2 to each term, we get the solution 3 < x < 7, or in interval notation (3, 7), as before.
  33. 33. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 6 CHAPTER 0 .. Preliminaries 0-6 The Cartesian Plane For any two real numbers x and y we visualize the ordered pair (x, y) as a point in two dimensions. The Cartesian plane is a plane with two real number lines drawn at right angles. The horizontal line is called the x-axis and the vertical line is called the y-axis. The point where the axes cross is called the origin, which represents the ordered pair (0, 0). To represent the ordered pair (1, 2), start at the origin, move 1 unit to the right and 2 units up and mark the point (1, 2), as in Figure 0.10. In example 1.8, we analyze a small set of experimental data by plotting some points in the Cartesian plane. This simple type of graph is sometimes called a scatter plot. EXAMPLE 1.8 Using a Graph Obtained from a Table of Data Suppose that you drop an object from the top of a building and record how far the object has fallen at different times, as shown in the following table. Time (sec) 0 0.5 1.0 1.5 2.0 Distance (ft) 0 4 16 36 64 Plot the points in the Cartesian plane and discuss any patterns you notice. In particular, use the graph to predict how far the object will have fallen in 2.5 seconds. Solution Taking the rst coordinate (x) to represent time and the second coordinate (y) to represent distance, we plot the points (0, 0), (0.5, 4), (1, 16), (1.5, 36) and (2, 64), as seen in Figure 0.11. (1, 2) y x 2112 2 1 1 2 FIGURE 0.10 The Cartesian plane y x 1.0 2.00.5 1.5 40 60 20 Time Distance FIGURE 0.11 Scatter plot of data Notice that the points appear to be curving upward (like a parabola). To predict the y-value corresponding to x = 2.5 (i.e., the distance fallen at time 2.5 seconds), we assume that this pattern continues, so that the y-value would be much higher than 64. But, how much higher is reasonable? It helps now to refer back to the data. Notice that the change in height from x = 1.5 to x = 2 is 64 36 = 28 feet. Since Figure 0.11 suggests that the curve is bending upward, the change in height between successive points should be getting larger and larger. You might reasonably predict that the height will change by more than 28. If you look carefully at the data, you might notice a pattern. Observe that the distances given at 0.5-second intervals are 02 , 22 , 42 , 62 and 82 . A reasonable guess for the distance at time 2.5 seconds might then be 102 = 100. Further, notice that this corresponds to a change of 36 from the distance at x = 2.0 seconds. At this stage, this is only an educated guess and other guesses (98 or 102, for example) might be equally reasonable. We urge that you think carefully about example 1.8. You should be comfortable with the interplay between the graph and the numerical data. This interplay will be a recurring theme in our study of calculus. The distance between two points in the Cartesian plane is a simple consequence of the Pythagorean Theorem, as follows. THEOREM 1.2 The distance between the points (x1, y1) and (x2, y2) in the Cartesian plane is given by d{(x1, y1), (x2, y2)} = (x2 x1)2 + (y2 y1)2 (1.5) PROOF We have oriented the points in Figure 0.12 so that (x2, y2) is above and to the right of (x1, y1). y x x2x1 y2 y1 y2 y1 x2 x1 Distance (x1, y1) (x2, y2) FIGURE 0.12 Distance Referring to the right triangle shown in Figure 0.12, notice that regardless of the orientation of the two points, the length of the horizontal side of the triangle is |x2 x1|
  34. 34. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 0-7 SECTION 0.1 .. The Real Numbers and the Cartesian Plane 7 and the length of the vertical side of the triangle is |y2 y1|. The distance between the two points is the length of the hypotenuse of the triangle, given by the Pythagorean Theorem as (x2 x1)2 + (y2 y1)2. We illustrate the use of the distance formula in example 1.9. EXAMPLE 1.9 Using the Distance Formula Find the distances between each pair of points (1, 2), (3, 4) and (2, 6). Use the distances to determine if the points form the vertices of a right triangle. y x 42 6 4 6 2 FIGURE 0.13 A right triangle? Solution The distance between (1, 2) and (3, 4) is d{(1, 2), (3, 4)} = (3 1)2 + (4 2)2 = 4 + 4 = 8. The distance between (1, 2) and (2, 6) is d{(1, 2), (2, 6)} = (2 1)2 + (6 2)2 = 1 + 16 = 17. Finally, the distance between (3, 4) and (2, 6) is d{(3, 4), (2, 6)} = (2 3)2 + (6 4)2 = 1 + 4 = 5. From a plot of the points (see Figure 0.13), it is unclear whether a right angle is formed at (3, 4). However, the sides of a right triangle must satisfy the Pythagorean Theorem. This would require that 8 2 + 5 2 = 17 2 . This is incorrect! Since this statement is not true, the triangle is not a right triangle. Again, we want to draw your attention to the interplay between graphical and algebraic techniques. If you master the relationship between graphs and equations, your study of calculus will be a more rewarding and enjoyable learning experience. EXERCISES 0.1 WRITING EXERCISES 1. To understand Denition 1.1, you must believe that |x| = x for negative xs. Using x = 3 as an example, explain in words why multiplying x by 1 produces the same result as taking the absolute value of x. 2. A common shortcut used to write inequalities is 4 < x < 4 in place of 4 < x and x < 4. Unfortunately, many people mistakenly write 4 < x < 4 in place of 4 < x or x < 4. Explain why the string 4 < x < 4 could never be true. (Hint: Whatdoesthisinequalitystringimplyaboutthenumbersonthe far left and far right? Here, you must write 4 < x or x < 4.) 3. Explain the result of Theorem 1.1 (ii) in your own words, as- suming that all constants involved are positive. 4. Suppose a friend has dug holes for the corner posts of a rect- angular deck. Explain how to use the Pythagorean Theorem to determine whether or not the holes truly form a rectangle (90 angles). In exercises 128, solve the inequality. 1. 3x + 2 < 11 2. 4x + 1 < 5 3. 2x 3 < 7 4. 3x 1 < 9 5. 4 3x < 6 6. 5 2x < 9 7. 4 x + 1 < 7 8. 1 < 2 x < 3 9. 2 < 2 2x < 3 10. 0 < 3 x < 1 11. x2 + 3x 4 > 0 12. x2 + 4x + 3 < 0 13. x2 x 6 < 0 14. x2 + 1 > 0 15. 3x2 + 4 > 0 16. x2 + 3x + 10 > 0 17. |x 3| < 4 18. |2x + 1| < 1 19. |3 x| < 1 20. |3 + x| > 1 21. |2x + 1| > 2 22. |3x 1| < 4 23. x + 2 x 2 > 0 24. x 4 x + 1 < 1 25. x2 x 2 (x + 4)2 > 0 26. 3 2x (x + 1)2 < 0 27. 8x (x + 1)3 < 0 28. x 2 (x + 2)3 > 0 ............................................................
  35. 35. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 8 CHAPTER 0 .. Preliminaries 0-8 In exercises 2934, nd the distance between the pair of points. 29. (2, 1), (4, 4) 30. (2, 1), (1, 4) 31. (1, 2), (3, 2) 32. (1, 2), (3, 6) 33. (0, 2), (2, 6) 34. (4, 1), (2, 1) ............................................................ In exercises 3538, determine if the set of points forms the ver- tices of a right triangle. 35. (1, 1), (3, 4), (0, 6) 36. (0, 2), (4, 8), (2, 12) 37. (2, 3), (2, 9), (4, 13) 38. (2, 3), (0, 6), (3, 8) ............................................................ In exercises 3942, the data represent populations at various times. Plot the points, discuss any patterns that are evident and predict the population at the next step. 39. (0, 1250), (1, 1800), (2, 2450), (3, 3200) 40. (0, 3160), (1, 3250), (2, 3360), (3, 3490) 41. (0, 4000), (1, 3990), (2, 3960), (3, 3910) 42. (0, 2100), (1, 2200), (2, 2100), (3, 1700) ............................................................ 43. As discussed in the text, a number is rational if and only if its decimal representation terminates or repeats. Calculators and computers perform their calculations using a nite number of digits. Explain why such calculations can only produce rational numbers. 44. In example 1.8, we discussed how the tendency of the data points to curve up corresponds to larger increases in consec- utive y-values. Explain why this is true. APPLICATIONS 45. The ancient Greeks analyzed music mathematically. They found that if pipes of length L and L 2 are struck, they make tones that blend together nicely. We say that these tones are one octave apart. In general, nice harmonies are produced by pipes (or strings) with rational ratios of lengths. For example, pipes of length L and 2 3 L form a fth (i.e., middle C and the G above middle C). On a piano keyboard, 12 fths are equal to 7 octaves. A glitch in piano tuning, known as the Pythagorean comma, results from the fact that 12 fths with total length ratio 2 3 12 do not equal 7 octaves with length ratio 1 2 7 . Show that the difference is about 1.3%. 46. For the 12 keys of a piano octave to have exactly the same length ratios (see exercise 45), the ratio of consecutive lengths should be a number x such that x12 = 2. Briey explain why. This means that x = 12 2. There are two problems with this equal-tempered tuning. First, 12 2 is irrational. Explain why it would be difcult to get the pipe or string exactly the right length. In any case, musicians say that equal-tempered pianos sound dull. 47. The use of squares in the Pythagorean Theorem has found a surprising use in the analysis of baseball statistics. In Bill James Historical Abstract, a rule is stated that a teams winning percentage P is approximately equal to R2 R2 + G2 , where R is the number of runs scored by the team and G is the number of runs scored against the team. For exam- ple, in 1996 the Texas Rangers scored 928 runs and gave up 799 runs. The formula predicts a winning percentage of 9282 9282 + 7992 0.574. In fact, Texas won 90 games and lost 72 for a winning percentage of 90 162 0.556. Fill out the follow- ing table (data from the 1996 season). What are possible ex- planations for teams that win more (or fewer) games than the formula predicts? Team R G P wins losses win % Yankees 871 787 92 70 Braves 773 648 96 66 Phillies 650 790 67 95 Dodgers 703 652 90 72 Indians 952 769 99 62 EXPLORATORY EXERCISES 1. It can be very difcult to prove that a given number is irrational. According to legend, the following proof that 2 is irrational so upset the ancient Greek mathematicians that they drowned a mathematician who revealed the result to the general public. The proof is by contradiction; that is, we imagine that 2 is rational and then show that this cannot be true. If 2 were rational, we would have that 2 = p q for some integers p and q. Assume that p q is in simplied form (i.e., any common fac- tors have been divided out). Square the equation 2 = p q to get 2 = p2 q2 . Explain why this can only be true if p is an even integer. Write p = 2r and substitute to get 2 = 4r2 q2 . Then, rearrange this expression to get q2 = 2r2 . Explain why this can only be true if q is an even integer. Something has gone wrong: explain why p and q cant both be even integers. Since this cant be true, we conclude that 2 is irrational. 2. In the text, we stated that a number is rational if and only if its decimal representation repeats or terminates. In this exercise, we prove that the decimal representation of any rational num- ber repeats or terminates. To start with a concrete example, use long division to show that 1 7 = 0.142857142857. Note that when you get a remainder of 1, its all over: you started with a 1 to divide into, so the sequence of digits must repeat. For a general rational number p q , there are q possible remainders (0, 1, 2, . . . , q 1). Explain why when doing long division you must eventually get a remainder you have had before. Explain why the digits will then either terminate or start repeating.
  36. 36. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 0-9 SECTION 0.2 .. Lines and Functions 9 0.2 LINES AND FUNCTIONS Equations of Lines The federal government conducts a nationwide census every 10 years to determine the popu- lation. Population data for several recent decades are shown in the accompanying table. Year U.S. Population 1960 179,323,175 1970 203,302,031 1980 226,542,203 1990 248,709,873 x y 0 179 10 203 20 227 30 249 Transformed data One difculty with analyzing these data is that the numbers are so large. This problem is remedied by transforming the data. We can simplify the year data by dening x to be the number of years since 1960, so that 1960 corresponds to x = 0, 1970 corresponds to x = 10 and so on. The population data can be simplied by rounding the numbers to the nearest million. The transformed data are shown in the accompanying table and a scatter plot of these data points is shown in Figure 0.14. The points in Figure 0.14 may appear to form a straight line. (Use a ruler and see if you agree.) To determine whether the points are, in fact, on the same line (such points are called colinear), we might consider the population growth in each of the indicated decades. From 1960 to 1970, the growth was 24 million. (That is, to move from the rst point to the second, you increase x by 10 and increase y by 24.) Likewise, from 1970 to 1980, the growth was 24 million. However, from 1980 to 1990, the growth was only 22 million. Since the rate of growth is not constant, the data points do not fall on a line. This argument involves the familiar concept of slope. y x 50 100 150 200 250 10 20 30 FIGURE 0.14 Population data DEFINITION 2.1 For x1 = x2, the slope of the straight line through the points (x1, y1) and (x2, y2) is the number m = y2 y1 x2 x1 . (2.1) When x1 = x2 and y1 = y2, the line through (x1, y1) and (x2, y2) is vertical and the slope is undened. We often describe slope as the change in y divided by the change in x, written y x , or more simply as Rise Run . (See Figure 0.15a.) Referring to Figure 0.15b (where the line has positive slope), notice that for any four points A, B, D and E on the line, the two right triangles ABC and DEF are similar. Recall that for similar triangles, the ratios of corresponding sides must be the same. x x x2 x1 Run y y2 y1 (x1, y1) (x2, y2) Rise y2 y1 x2x1 y y x x x y B E A D F C y FIGURE 0.15a Slope FIGURE 0.15b Similar triangles and slope
  37. 37. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 10 CHAPTER 0 .. Preliminaries 0-10 In this case, this says that y x = y x and so, the slope is the same no matter which two points on the line are selected. Notice that a line is horizontal if and only if its slope is zero. EXAMPLE 2.1 Finding the Slope of a Line Find the slope of the line through the points (4, 3) and (2, 5). Solution From (2.1), we get m = y2 y1 x2 x1 = 5 3 2 4 = 2 2 = 1. EXAMPLE 2.2 Using Slope to Determine If Points Are Colinear Use slope to determine whether the points (1, 2), (3, 10) and (4, 14) are colinear. Solution First, notice that the slope of the line joining (1, 2) and (3, 10) is m1 = y2 y1 x2 x1 = 10 2 3 1 = 8 2 = 4. Similarly, the slope through the line joining (3, 10) and (4, 14) is m2 = y2 y1 x2 x1 = 14 10 4 3 = 4. Since the slopes are the same, the points must be colinear. Recall that if you know the slope and a point through which the line must pass, you have enough information to graph the line. The easiest way to graph a line is to plot two points and then draw the line through them. In this case, you need only to nd a second point. EXAMPLE 2.3 Graphing a Line If a line passes through the point (2, 1) with slope 2 3 , nd a second point on the line and then graph the line. Solution Since slope is given by m = y2 y1 x2 x1 , we take m = 2 3 , y1 = 1 and x1 = 2, to obtain 2 3 = y2 1 x2 2 . You are free to choose the x-coordinate of the second point. For instance, to nd the point at x2 = 5, substitute this in and solve. From 2 3 = y2 1 5 2 = y2 1 3 , we get 2 = y2 1 or y2 = 3. A second point is then (5, 3). The graph of the line is shown in Figure 0.16a. An alternative method for nding a second point is to use the slope m = 2 3 = y x . The slope of 2 3 says that if we move three units to the right, we must move two units up to stay on the line, as illustrated in Figure 0.16b. y x 1 1 2 3 4 1 5432 FIGURE 0.16a Graph of straight line y x 1 1 2 3 4 1 5432 x 3 y2 FIGURE 0.16b Using slope to nd a second point In example 2.3, the choice of x = 5 was entirely arbitrary; you can choose any x-value you want to nd a second point. Further, since x can be any real number, you
  38. 38. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 0-11 SECTION 0.2 .. Lines and Functions 11 can leave x as a variable and write out an equation satised by any point (x, y) on the line. In the general case of the line through the point (x0, y0) with slope m, we have from (2.1) that m = y y0 x x0 . (2.2) Multiplying both sides of (2.2) by (x x0), we get y y0 = m(x x0) or POINT-SLOPE FORM OF A LINE y = m(x x0) + y0. (2.3) Equation (2.3) is called the point-slope form of the line. EXAMPLE 2.4 Finding the Equation of a Line Given Two Points Find an equation of the line through the points (3, 1) and (4, 1) and graph the line. Solution From (2.1), the slope is m = 1 1 4 3 = 2 1 = 2. Using (2.3) with slope m = 2, x-coordinate x0 = 3 and y-coordinate y0 = 1, we get the equation of the line: y = 2(x 3) + 1. (2.4) To graph the line, plot the points (3, 1) and (4, 1), and you can easily draw the line seen in Figure 0.17. y x 1 1 2 3 4 5 6 7 1 2 3 4 FIGURE 0.17 y = 2(x 3) + 1 Although the point-slope form of the equation is often the most convenient to work with, the slope-intercept form is sometimes more convenient. This has the form y = mx + b, where m is the slope and b is the y-intercept (i.e., the place where the graph crosses the y-axis). In example 2.4, you simply multiply out (2.4) to get y = 2x + 6 + 1 or y = 2x + 7. As you can see from Figure 0.17, the graph crosses the y-axis at y = 7. Theorem 2.1 presents a familiar result on parallel and perpendicular lines. THEOREM 2.1 Two (nonvertical) lines are parallel if they have the same slope. Further, any two vertical lines are parallel. Two (nonvertical) lines of slope m1 and m2 are perpendicular whenever the product of their slopes is 1 (i.e., m1 m2 = 1). Also, any vertical line and any horizontal line are perpendicular. Since we can read the slope from the equation of a line, its a simple matter to de- termine when two lines are parallel or perpendicular. We illustrate this in examples 2.5 and 2.6.
  39. 39. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 12 CHAPTER 0 .. Preliminaries 0-12 EXAMPLE 2.5 Finding the Equation of a Parallel Line Find an equation of the line parallel to y = 3x 2 and through the point (1, 3). y x 10 20 10 20 4224 FIGURE 0.18 Parallel lines Solution Its easy to read the slope of the line from the equation: m = 3. The equation of the parallel line is then y = 3[x (1)] + 3 or simply y = 3x + 6. We show a graph of both lines in Figure 0.18. EXAMPLE 2.6 Finding the Equation of a Perpendicular Line Find an equation of the line perpendicular to y = 2x + 4 and intersecting the line at the point (1, 2). Solution The slope of y = 2x + 4 is 2. The slope of the perpendicular line is then 1/(2) = 1 2 . Since the line must pass through the point (1, 2), the equation of the perpendicular line is y = 1 2 (x 1) + 2 or y = 1 2 x + 3 2 . We show a graph of the two lines in Figure 0.19. y x 4 2 2 4 2 42 FIGURE 0.19 Perpendicular lines We now return to this sections introductory example and use the equation of a line to estimate the population in the year 2000. EXAMPLE 2.7 Using a Line to Predict Population Given the population data for the census years 1960, 1970, 1980 and 1990, predict the population for the year 2000. Solution We began this section by showing that the points in the corresponding table are not colinear. Nonetheless, they are nearly colinear. So, why not use the straight line connecting the last two points (20, 227) and (30, 249) (corresponding to the populations in the years 1980 and 1990) to predict the population in 2000? (This is a simple example of a more general procedure called extrapolation.) The slope of the line joining the two data points is m = 249 227 30 20 = 22 10 = 11 5 . The equation of the line is then y = 11 5 (x 30) + 249. y x 5040302010 100 200 300 FIGURE 0.20 Population See Figure 0.20 for a graph of the line. If we follow this line to the point corresponding to x = 40 (the year 2000), we have the predicted population 11 5 (40 30) + 249 = 271. That is, the predicted population is 271 million people. The actual census gure for 2000 was 281 million, which indicates that the U.S. population grew at a faster rate between 1990 and 2000 than in the previous decade. f x BA y Functions For any two subsets A and B of the real line, we make the following familiar denition.
  40. 40. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 0-13 SECTION 0.2 .. Lines and Functions 13 DEFINITION 2.2 A function f is a rule that assigns exactly one element y in a set B to each element x in a set A. In this case, we write y = f (x). We call the set A the domain of f. The set of all values f (x) in B is called the range of f , written {y|y = f (x), for some x A}. Unless explicitly stated otherwise, whenever a function f is given by a particular expression, the domain of f is the largest set of real numbers for which the expression is dened. We refer to x as the independent variable and to y as the dependent variable. REMARK 2.1 Functions can be dened by simple formulas, such as f (x) = 3x + 2, but in general, any correspondence meeting the requirement of matching exactly one y to each x denes a function. By the graph of a function f, we mean the graph of the equation y = f (x). That is, the graph consists of all points (x, y), where x is in the domain of f and where y = f (x). Notice that not every curve is the graph of a function, since for a function, only one y-value can correspond to a given value of x. You can graphically determine whether a curve is the graph of a function by using the vertical line test: if any vertical line intersects the graph in more than one point, the curve is not the graph of a function, since in this case, there are two y-values for a given value of x. EXAMPLE 2.8 Using the Vertical Line Test Determine which of the curves in Figures 0.21a and 0.21b correspond to functions. y x 11 y x 0.5 21 1 1 FIGURE 0.21a FIGURE 0.21b Solution Notice that the circle in Figure 0.21a is not the graph of a function, since a vertical line at x = 0.5 intersects the circle twice. (See Figure 0.22a.) The graph in Figure 0.21b is the graph of a function, even though it swings up and down repeatedly. Although horizontal lines intersect the graph repeatedly, vertical lines, such as the one at x = 1.2, intersect only once. (See Figure 0.22b.) The functions with which you are probably most familiar are polynomials. These are the simplest functions to work with because they are dened entirely in terms of arithmetic. y x 10.51 FIGURE 0.22a Curve fails vertical line test y x 0.5 21 1 1 FIGURE 0.22b Curve passes vertical line test DEFINITION 2.3 A polynomial is any function that can be written in the form f (x) = an xn + an1xn1 + + a1x + a0, where a0, a1, a2, . . . , an are real numbers (the coefcients of the polynomial) with an = 0 and n 0 is an integer (the degree of the polynomial).
  41. 41. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 14 CHAPTER 0 .. Preliminaries 0-14 Note that every polynomial function can be dened for all xs on the entire real line. Further, recognize that the graph of the linear (degree 1) polynomial f (x) = ax + b is a straight line. EXAMPLE 2.9 Sample Polynomials The following are all examples of polynomials: f (x) = 2 (polynomial of degree 0 or constant), f (x) = 3x + 2 (polynomial of degree 1 or linear polynomial), f (x) = 5x2 2x + 2 3 (polynomial of degree 2 or quadratic polynomial), f (x) = x3 2x + 1 (polynomial of degree 3 or cubic polynomial), f (x) = 6x4 + 12x2 3x + 13 (polynomial of degree 4 or quartic polynomial) and f (x) = 2x5 + 6x4 8x2 + x 3 (polynomial of degree 5 or quintic polynomial). We show graphs of these six functions in Figures 0.23a0.23f. y x 1 3 y x 4224 15 10 5 5 10 15 y x 642246 40 80 120 FIGURE 0.23a f (x) = 2 FIGURE 0.23b f (x) = 3x + 2 FIGURE 0.23c f (x) = 5x2 2x + 2 3 y x 321123 10 5 5 10 y x 2112 20 10 10 20 y x 13 2 1 10 10 20 FIGURE 0.23d f (x) = x3 2x + 1 FIGURE 0.23e f (x) = 6x4 + 12x2 3x + 13 FIGURE 0.23f f (x) = 2x5 + 6x4 8x2 + x 3
  42. 42. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 0-15 SECTION 0.2 .. Lines and Functions 15 DEFINITION 2.4 Any function that can be written in the form f (x) = p(x) q(x) , where p and q are polynomials, is called a rational function. Notice that since p and q are polynomials, they can both be dened for all x and so, the rational function f (x) = p(x) q(x) can be dened for all x for which q(x) = 0. EXAMPLE 2.10 A Sample Rational Function Find the domain of the function f (x) = x2 + 7x 11 x2 4 . Solution Here, f is a rational function. We show a graph in Figure 0.24. Its domain consists of those values of x for which the denominator is nonzero. Notice that x2 4 = (x 2)(x + 2) and so, the denominator is zero if and only if x = 2. This says that the domain of f is {x R|x = 2} = (, 2) (2, 2) (2, ). y x 1 313 10 5 5 10 FIGURE 0.24 f (x) = x2 + 7x 11 x2 4 The square root function is dened in the usual way. When we write y = x, we mean that y is that number for which y2 = x and y 0. In particular, 4 = 2. Be careful not to write erroneous statements such as 4 = 2. In particular, be careful to write x2 = |x|. Since x2 is asking for the nonnegative number whose square is x2 , we are looking for |x| and not x. We can say x2 = x, only for x 0. Similarly, for any integer n 2, y = n x whenever yn = x, where for n even, x 0 and y 0. EXAMPLE 2.11 Finding the Domain of a Function Involving a Square Root or a Cube Root Find the domains of f (x) = x2 4 and g(x) = 3 x2 4. Solution Since even roots are dened only for nonnegative values, f (x) is dened only for x2 4 0. Notice that this is equivalent to having x2 4, which occurs when x 2 or x 2. The domain of f is then (, 2] [2, ). On the other hand, odd roots are dened for both positive and negative values. Consequently, the domain of g is the entire real line, (, ). We often nd it useful to label intercepts and other signicant points on a graph. Finding these points typically involves solving equations. A solution of the equation f (x) = 0 is called a zero of the function f or a root of the equation f (x) = 0. Notice that a zero of the function f corresponds to an x-intercept of the graph of y = f (x).
  43. 43. P1: OSO/OVY P2: OSO/OVY QC: OSO/OVY T1: OSO MHDQ256-Ch00 MHDQ256-Smith-v1.cls December 8, 2010 15:25 LT (Late Transcendental) CONFIRMING PAGES 16 CHAPTER 0 .. Preliminaries 0-16 EXAMPLE 2.12 Finding Zeros by Factoring Find all x- and y-intercepts of f (x) = x2 4x + 3. Solution To nd the y-intercept, set x = 0 to obtain y = 0 0 + 3 = 3. To nd the x-intercepts, solve the equation f (x) = 0. In this case, we can factor to get f (x) = x2 4x + 3 = (x 1)(x 3) = 0. You can now read off the zeros: x = 1 and x = 3, as indicated in Figure 0.25. y x 2 4 6 8 10 321 4 62 FIGURE 0.25 y = x2 4x + 3 Unfortunately, factoring is not always so easy. Of course, for the quadratic equation ax2 + bx + c = 0 (for a = 0), the solution(s) are given by the familiar quadratic formula: x = b b2 4ac 2a . EXAMPLE 2.13 Finding Zeros Using the Quadratic Formula Find the zeros of f (x) = x2 5