Thomas Calculus 12th Edition Textbook and helping material

Based on the original work by
George B. Thomas, Jr.
Massachusetts Institute of Technology
as revised by
Maurice D. Weir
Naval Postgraduate School
Joel Hass
University of California, Davis
THOMAS’
CALCULUS
EARLY TRANSCENDENTALS
Twelfth Edition
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was taken in Hokkaido, Japan. The artist was not thinking of calculus when he composed the image, but rather, of a
visual haiku consisting of a few elements that would spark the viewer’s imagination. Similarly, the minimal design
of this text allows the central ideas of calculus developed in this book to unfold to ignite the learner’s imagination.
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Library of Congress Cataloging-in-Publication Data
Weir, Maurice D.
Thomas’ calculus : early transcendentals / Maurice D. Weir, Joel Hass, George B. Thomas.—12th ed.
p. cm
Includes index.
ISBN 978-0-321-58876-0
1. Calculus—Textbooks. 2. Geometry, Analytic—Textbooks. I. Hass, Joel. II. Thomas, George B. (George
Brinton), 1914–2006. III. Title IV
. Title: Calculus.
QA303.2.W45 2009
515—dc22 2009023070
Copyright © 2010, 2006, 2001 Pearson Education, Inc. All rights reserved. No part of this publication may be
reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without the prior written permission of the publisher. Printed in the United
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1 2 3 4 5 6 7 8 9 10—CRK—12 11 10 09
ISBN-10: 0-321-58876-2
www.pearsoned.com ISBN-13: 978-0-321-58876-0
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iii
Preface ix
1 Functions 1
1.1 Functions and Their Graphs 1
1.2 Combining Functions; Shifting and Scaling Graphs 14
1.3 Trigonometric Functions 22
1.4 Graphing with Calculators and Computers 30
1.5 Exponential Functions 34
1.6 Inverse Functions and Logarithms 40
QUESTIONS TO GUIDE YOUR REVIEW 52
PRACTICE EXERCISES 53
ADDITIONAL AND ADVANCED EXERCISES 55
2
Limits and Continuity 58
2.1 Rates of Change and Tangents to Curves 58
2.2 Limit of a Function and Limit Laws 65
2.3 The Precise Definition of a Limit 76
2.4 One-Sided Limits 85
2.5 Continuity 92
2.6 Limits Involving Infinity; Asymptotes of Graphs 103
3
Differentiation 122
3.1 Tangents and the Derivative at a Point 122
3.2 The Derivative as a Function 126
CONTENTS
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3.3 Differentiation Rules 135
3.4 The Derivative as a Rate of Change 145
3.5 Derivatives of Trigonometric Functions 155
3.6 The Chain Rule 162
3.7 Implicit Differentiation 170
3.8 Derivatives of Inverse Functions and Logarithms 176
3.9 Inverse Trigonometric Functions 186
3.10 Related Rates 192
3.11 Linearization and Differentials 201
4
Applications of Derivatives 222
4.1 Extreme Values of Functions 222
4.2 The Mean Value Theorem 230
4.3 Monotonic Functions and the First Derivative Test 238
4.4 Concavity and Curve Sketching 243
4.5 Indeterminate Forms and L
’Hôpital’s Rule 254
4.6 Applied Optimization 263
4.7 Newton’s Method 274
4.8 Antiderivatives 279
5
Integration 297
5.1 Area and Estimating with Finite Sums 297
5.2 Sigma Notation and Limits of Finite Sums 307
5.3 The Definite Integral 313
5.4 The Fundamental Theorem of Calculus 325
5.5 Indefinite Integrals and the Substitution Method 336
5.6 Substitution and Area Between Curves 344
6
Applications of Definite Integrals 363
6.1 Volumes Using Cross-Sections 363
6.2 Volumes Using Cylindrical Shells 374
6.3 Arc Length 382
iv Contents
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6.4 Areas of Surfaces of Revolution 388
6.5 Work and Fluid Forces 393
6.6 Moments and Centers of Mass 402
7
Integrals and Transcendental Functions 417
7.1 The Logarithm Defined as an Integral 417
7.2 Exponential Change and Separable Differential Equations 427
7.3 Hyperbolic Functions 436
7.4 Relative Rates of Growth 444
8
Techniques of Integration 453
8.1 Integration by Parts 454
8.2 Trigonometric Integrals 462
8.3 Trigonometric Substitutions 467
8.4 Integration of Rational Functions by Partial Fractions 471
8.5 Integral Tables and Computer Algebra Systems 481
8.6 Numerical Integration 486
8.7 Improper Integrals 496
9
First-Order Differential Equations 514
9.1 Solutions, Slope Fields, and Euler’s Method 514
9.2 First-Order Linear Equations 522
9.3 Applications 528
9.4 Graphical Solutions of Autonomous Equations 534
9.5 Systems of Equations and Phase Planes 541
10
Infinite Sequences and Series 550
10.1 Sequences 550
10.2 Infinite Series 562
Contents v
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10.3 The Integral Test 571
10.4 Comparison Tests 576
10.5 The Ratio and Root Tests 581
10.6 Alternating Series, Absolute and Conditional Convergence 586
10.7 Power Series 593
10.8 Taylor and Maclaurin Series 602
10.9 Convergence of Taylor Series 607
10.10 The Binomial Series and Applications of Taylor Series 614
11
Parametric Equations and Polar Coordinates 628
11.1 Parametrizations of Plane Curves 628
11.2 Calculus with Parametric Curves 636
11.3 Polar Coordinates 645
11.4 Graphing in Polar Coordinates 649
11.5 Areas and Lengths in Polar Coordinates 653
11.6 Conic Sections 657
11.7 Conics in Polar Coordinates 666
12
Vectors and the Geometry of Space 678
12.1 Three-Dimensional Coordinate Systems 678
12.2 Vectors 683
12.3 The Dot Product 692
12.4 The Cross Product 700
12.5 Lines and Planes in Space 706
12.6 Cylinders and Quadric Surfaces 714
13
Vector-Valued Functions and Motion in Space 725
13.1 Curves in Space and Their Tangents 725
13.2 Integrals of Vector Functions; Projectile Motion 733
13.3 Arc Length in Space 742
13.4 Curvature and Normal Vectors of a Curve 746
13.5 Tangential and Normal Components of Acceleration 752
13.6 Velocity and Acceleration in Polar Coordinates 757
vi Contents
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14
Partial Derivatives 765
14.1 Functions of Several Variables 765
14.2 Limits and Continuity in Higher Dimensions 773
14.3 Partial Derivatives 782
14.4 The Chain Rule 793
14.5 Directional Derivatives and Gradient Vectors 802
14.6 Tangent Planes and Differentials 809
14.7 Extreme Values and Saddle Points 820
14.8 Lagrange Multipliers 829
14.9 Taylor’s Formula for Two Variables 838
14.10 Partial Derivatives with Constrained Variables 842
15
Multiple Integrals 854
15.1 Double and Iterated Integrals over Rectangles 854
15.2 Double Integrals over General Regions 859
15.3 Area by Double Integration 868
15.4 Double Integrals in Polar Form 871
15.5 Triple Integrals in Rectangular Coordinates 877
15.6 Moments and Centers of Mass 886
15.7 Triple Integrals in Cylindrical and Spherical Coordinates 893
15.8 Substitutions in Multiple Integrals 905
16
Integration in Vector Fields 919
16.1 Line Integrals 919
16.2 Vector Fields and Line Integrals: Work, Circulation, and Flux 925
16.3 Path Independence, Conservative Fields, and Potential Functions 938
16.4 Green’s Theorem in the Plane 949
16.5 Surfaces and Area 961
16.6 Surface Integrals 971
Contents vii
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16.7 Stokes’Theorem 980
16.8 The Divergence Theorem and a Unified Theory 990
17
Second-Order Differential Equations online
17.1 Second-Order Linear Equations
17.2 Nonhomogeneous Linear Equations
17.3 Applications
17.4 Euler Equations
17.5 Power Series Solutions
Appendices AP-1
A.1 Real Numbers and the Real Line AP-1
A.2 Mathematical Induction AP-6
A.3 Lines, Circles, and Parabolas AP-10
A.4 Proofs of Limit Theorems AP-18
A.5 Commonly Occurring Limits AP-21
A.6 Theory of the Real Numbers AP-23
A.7 Complex Numbers AP-25
A.8 The Distributive Law for Vector Cross Products AP-35
A.9 The Mixed Derivative Theorem and the Increment Theorem AP-36
Answers to Odd-Numbered Exercises A-1
Index I-1
Credits C-1
A Brief Table of Integrals T-1
viii Contents
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We have significantly revised this edition of Thomas’ Calculus: Early Transcendentals to
meet the changing needs of today’s instructors and students. The result is a book with more
examples, more mid-level exercises, more figures, better conceptual flow, and increased
clarity and precision. As with previous editions, this new edition provides a modern intro-
duction to calculus that supports conceptual understanding but retains the essential ele-
ments of a traditional course. These enhancements are closely tied to an expanded version
of MyMathLab®
for this text (discussed further on), providing additional support for stu-
dents and flexibility for instructors.
In this twelfth edition early transcendentals version, we introduce the basic transcen-
dental functions in Chapter 1. After reviewing the basic trigonometric functions, we pres-
ent the family of exponential functions using an algebraic and graphical approach, with
the natural exponential described as a particular member of this family. Logarithms are
then defined as the inverse functions of the exponentials, and we also discuss briefly the
inverse trigonometric functions. We fully incorporate these functions throughout our de-
velopments of limits, derivatives, and integrals in the next five chapters of the book, in-
cluding the examples and exercises. This approach gives students the opportunity to work
early with exponential and logarithmic functions in combinations with polynomials, ra-
tional and algebraic functions, and trigonometric functions as they learn the concepts, oper-
ations, and applications of single-variable calculus. Later, in Chapter 7, we revisit the defi-
nition of transcendental functions, now giving a more rigorous presentation. Here we define
the natural logarithm function as an integral with the natural exponential as its inverse.
Many of our students were exposed to the terminology and computational aspects of
calculus during high school. Despite this familiarity, students’ algebra and trigonometry
skills often hinder their success in the college calculus sequence. With this text, we have
sought to balance the students’ prior experience with calculus with the algebraic skill de-
velopment they may still need, all without undermining or derailing their confidence. We
have taken care to provide enough review material, fully stepped-out solutions, and exer-
cises to support complete understanding for students of all levels.
We encourage students to think beyond memorizing formulas and to generalize con-
cepts as they are introduced. Our hope is that after taking calculus, students will be confi-
dent in their problem-solving and reasoning abilities. Mastering a beautiful subject with
practical applications to the world is its own reward, but the real gift is the ability to think
and generalize. We intend this book to provide support and encouragement for both.
Changes for the Twelfth Edition
CONTENT In preparing this edition we have maintained the basic structure of the Table of
Contents from the eleventh edition, yet we have paid attention to requests by current users
and reviewers to postpone the introduction of parametric equations until we present polar
coordinates. We have made numerous revisions to most of the chapters, detailed as follows:
ix
PREFACE
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• Functions We condensed this chapter to focus on reviewing function concepts and in-
troducing the transcendental functions. Prerequisite material covering real numbers, in-
tervals, increments, straight lines, distances, circles, and parabolas is presented in Ap-
pendices 1–3.
• Limits To improve the flow of this chapter, we combined the ideas of limits involving
infinity and their associations with asymptotes to the graphs of functions, placing them
together in the final section of Chapter 3.
• Differentiation While we use rates of change and tangents to curves as motivation for
studying the limit concept, we now merge the derivative concept into a single chapter.
We reorganized and increased the number of related rates examples, and we added new
examples and exercises on graphing rational functions. L
’Hôpital’s Rule is presented as
an application section, consistent with our early coverage of the transcendental functions.
• Antiderivatives and Integration We maintain the organization of the eleventh edition
in placing antiderivatives as the final topic of Chapter 4, covering applications of
derivatives. Our focus is on “recovering a function from its derivative” as the solution
to the simplest type of first-order differential equation. Integrals, as “limits of Riemann
sums,” motivated primarily by the problem of finding the areas of general regions with
curved boundaries, are a new topic forming the substance of Chapter 5. After carefully
developing the integral concept, we turn our attention to its evaluation and connection
to antiderivatives captured in the Fundamental Theorem of Calculus. The ensuing ap-
plications then define the various geometric ideas of area, volume, lengths of paths, and
centroids, all as limits of Riemann sums giving definite integrals, which can be evalu-
ated by finding an antiderivative of the integrand. We return later to the topic of solving
more complicated first-order differential equations.
• Differential Equations Some universities prefer that this subject be treated in a course
separate from calculus. Although we do cover solutions to separable differential equations
when treating exponential growth and decay applications in Chapter 7 on integrals and
transcendental functions, we organize the bulk of our material into two chapters (which
may be omitted for the calculus sequence). We give an introductory treatment of first-
order differential equations in Chapter 9, including a new section on systems and
phase planes, with applications to the competitive-hunter and predator-prey models. We
present an introduction to second-order differential equations in Chapter 17, which is in-
cluded in MyMathLab as well as the Thomas’Calculus: Early Transcendentals Web site,
www.pearsonhighered.com/thomas.
• Series We retain the organizational structure and content of the eleventh edition for the
topics of sequences and series. We have added several new figures and exercises to the
various sections, and we revised some of the proofs related to convergence of power se-
ries in order to improve the accessibility of the material for students. The request stated
by one of our users as, “anything you can do to make this material easier for students
will be welcomed by our faculty,” drove our thinking for revisions to this chapter.
• Parametric Equations Several users requested that we move this topic into Chapter
11, where we also cover polar coordinates and conic sections. We have done this, realiz-
ing that many departments choose to cover these topics at the beginning of Calculus III,
in preparation for their coverage of vectors and multivariable calculus.
• Vector-Valued Functions We streamlined the topics in this chapter to place more em-
phasis on the conceptual ideas supporting the later material on partial derivatives, the
gradient vector, and line integrals. We condensed the discussions of the Frenet frame
and Kepler’s three laws of planetary motion.
• Multivariable Calculus We have further enhanced the art in these chapters, and we
have added many new figures, examples, and exercises. We reorganized the opening
material on double integrals, and we combined the applications of double and triple
integrals to masses and moments into a single section covering both two- and three-
dimensional cases. This reorganization allows for better flow of the key mathematical
concepts, together with their properties and computational aspects. As with the
x Preface
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eleventh edition, we continue to make the connections of multivariable ideas with their
single-variable analogues studied earlier in the book.
• Vector Fields We devoted considerable effort to improving the clarity and mathemati-
cal precision of our treatment of vector integral calculus, including many additional ex-
amples, figures, and exercises. Important theorems and results are stated more clearly
and completely, together with enhanced explanations of their hypotheses and mathe-
matical consequences. The area of a surface is now organized into a single section, and
surfaces defined implicitly or explicitly are treated as special cases of the more general
parametric representation. Surface integrals and their applications then follow as a sep-
arate section. Stokes’ Theorem and the Divergence Theorem are still presented as gen-
eralizations of Green’s Theorem to three dimensions.
EXERCISES AND EXAMPLES We know that the exercises and examples are critical com-
ponents in learning calculus. Because of this importance, we have updated, improved, and
increased the number of exercises in nearly every section of the book. There are over 700
new exercises in this edition. We continue our organization and grouping of exercises by
topic as in earlier editions, progressing from computational problems to applied and theo-
retical problems. Exercises requiring the use of computer software systems (such as
Maple®
or Mathematica®
) are placed at the end of each exercise section, labeled Com-
puter Explorations. Most of the applied exercises have a subheading to indicate the kind
of application addressed in the problem.
Many sections include new examples to clarify or deepen the meaning of the topic be-
ing discussed and to help students understand its mathematical consequences or applica-
tions to science and engineering. At the same time, we have removed examples that were a
repetition of material already presented.
ART Because of their importance to learning calculus, we have continued to improve exist-
ing figures in Thomas’ Calculus: Early Transcendentals, and we have created a significant
number of new ones. We continue to use color consistently and pedagogically to enhance the
conceptual idea that is being illustrated. We have also taken a fresh look at all of the figure
captions, paying considerable attention to clarity and precision in short statements.
FIGURE 2.50, page 104 The geometric FIGURE 16.9, page 926 A surface in a
explanation of a finite limit as . space occupied by a moving fluid.
MYMATHLAB AND MATHXL The increasing use of and demand for online homework
systems has driven the changes to MyMathLab and MathXL®
for Thomas’ Calculus:
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Preface xi
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Early Transcendentals. The MyMathLab course now includes significantly more exer-
cises of all types.
Continuing Features
RIGOR The level of rigor is consistent with that of earlier editions. We continue to distin-
guish between formal and informal discussions and to point out their differences. We think
starting with a more intuitive, less formal, approach helps students understand a new or diffi-
cult concept so they can then appreciate its full mathematical precision and outcomes. We pay
attention to defining ideas carefully and to proving theorems appropriate for calculus students,
while mentioning deeper or subtler issues they would study in a more advanced course. Our
organization and distinctions between informal and formal discussions give the instructor a de-
gree of flexibility in the amount and depth of coverage of the various topics. For example, while
we do not prove the Intermediate Value Theorem or the Extreme Value Theorem for continu-
ous functions on , we do state these theorems precisely, illustrate their meanings in
numerous examples, and use them to prove other important results. Furthermore, for those in-
structors who desire greater depth of coverage, in Appendix 6 we discuss the reliance of the
validity of these theorems on the completeness of the real numbers.
WRITING EXERCISES Writing exercises placed throughout the text ask students to ex-
plore and explain a variety of calculus concepts and applications. In addition, the end of
each chapter contains a list of questions for students to review and summarize what they
have learned. Many of these exercises make good writing assignments.
END-OF-CHAPTER REVIEWS AND PROJECTS In addition to problems appearing after
each section, each chapter culminates with review questions, practice exercises covering
the entire chapter, and a series of Additional and Advanced Exercises serving to include
more challenging or synthesizing problems. Most chapters also include descriptions of
several Technology Application Projects that can be worked by individual students or
groups of students over a longer period of time. These projects require the use of a com-
puter running Mathematica or Maple and additional material that is available over the
Internet at www.pearsonhighered.com/thomas and in MyMathLab.
WRITING AND APPLICATIONS As always, this text continues to be easy to read, conversa-
tional, and mathematically rich. Each new topic is motivated by clear, easy-to-understand
examples and is then reinforced by its application to real-world problems of immediate in-
terest to students. A hallmark of this book has been the application of calculus to science
and engineering. These applied problems have been updated, improved, and extended con-
tinually over the last several editions.
TECHNOLOGY In a course using the text, technology can be incorporated according to the
taste of the instructor. Each section contains exercises requiring the use of technology;
these are marked with a if suitable for calculator or computer use, or they are labeled
Computer Explorations if a computer algebra system (CAS, such as Maple or Mathe-
matica) is required.
Text Versions
THOMAS’ CALCULUS: EARLY TRANSCENDENTALS, Twelfth Edition
Complete (Chapters 1–16), ISBN 0-321-58876-2 | 978-0-321-58876-0
Single Variable Calculus (Chapters 1–11), 0-321-62883-7 | 978-0-321-62883-1
Multivariable Calculus (Chapters 10–16), ISBN 0-321-64369-0 | 978-0-321-64369-8
T
a … x … b
xii Preface
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The early transcendentals version of Thomas’ Calculus introduces and integrates transcen-
dental functions (such as inverse trigonometric, exponential, and logarithmic functions)
into the exposition, examples, and exercises of the early chapters alongside the algebraic
functions. The Multivariable book for Thomas’ Calculus: Early Transcendentals is the
same text as Thomas’Calculus, Multivariable.
THOMAS’ CALCULUS, Twelfth Edition
Complete (Chapters 1–16), ISBN 0-321-58799-5 | 978-0-321-58799-2
Single Variable Calculus (Chapters 1–11), ISBN 0-321-63742-9 | 978-0-321-63742-0
Instructor’s Editions
Thomas’Calculus: Early Transcendentals, ISBN 0-321-62718-0 | 978-0-321-62718-6
Thomas’Calculus, ISBN 0-321-60075-4 | 978-0-321-60075-2
In addition to including all of the answers present in the student editions, the Instructor’s
Editions include even-numbered answers for Chapters 1–6.
University Calculus (Early Transcendentals)
University Calculus: Alternate Edition (Late Transcendentals)
University Calculus: Elements with Early Transcendentals
The University Calculus texts are based on Thomas’ Calculus and feature a streamlined
presentation of the contents of the calculus course. For more information about these titles,
visit www.pearsonhighered.com.
Print Supplements
INSTRUCTOR’S SOLUTIONS MANUAL
Single Variable Calculus (Chapters 1–11), ISBN 0-321-62717-2 | 978-0-321-62717-9
Multivariable Calculus (Chapters 10–16), ISBN 0-321-60072-X | 978-0-321-60072-1
The Instructor’s Solutions Manual by William Ardis, Collin County Community College,
contains complete worked-out solutions to all of the exercises in Thomas’ Calculus: Early
Transcendentals.
STUDENT’S SOLUTIONS MANUAL
Single Variable Calculus (Chapters 1–11), ISBN 0-321-65692-X | 978-0-321-65692-6
The Student’s Solutions Manual by William Ardis, Collin County Community College, is
designed for the student and contains carefully worked-out solutions to all the odd-
numbered exercises in Thomas’Calculus: Early Transcendentals.
JUST-IN-TIME ALGEBRA AND TRIGONOMETRY FOR EARLY TRANSCENDENTALS
CALCULUS, Third Edition
ISBN 0-321-32050-6 | 978-0-321-32050-6
Sharp algebra and trigonometry skills are critical to mastering calculus, and Just-in-Time
Algebra and Trigonometry for Early Transcendentals Calculus by Guntram Mueller and
Ronald I. Brent is designed to bolster these skills while students study calculus. As stu-
dents make their way through calculus, this text is with them every step of the way, show-
ing them the necessary algebra or trigonometry topics and pointing out potential problem
spots. The easy-to-use table of contents has algebra and trigonometry topics arranged in
the order in which students will need them as they study calculus.
CALCULUS REVIEW CARDS
The Calculus Review Cards (one for Single Variable and another for Multivariable) are a
student resource containing important formulas, functions, definitions, and theorems that
correspond precisely to the Thomas’ Calculus series. These cards can work as a reference
for completing homework assignments or as an aid in studying, and are available bundled
with a new text. Contact your Pearson sales representative for more information.
Preface xiii
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Media and Online Supplements
TECHNOLOGY RESOURCE MANUALS
Maple Manual by James Stapleton, North Carolina State University
Mathematica Manual by Marie Vanisko, Carroll College
TI-Graphing Calculator Manual by Elaine McDonald-Newman, Sonoma State University
These manuals cover Maple 13, Mathematica 7, and the TI-83 Plus/TI-84 Plus and TI-89,
respectively. Each manual provides detailed guidance for integrating a specific software
package or graphing calculator throughout the course, including syntax and commands.
These manuals are available to qualified instructors through the Thomas’ Calculus: Early
Transcendentals Web site, www.pearsonhighered.com/thomas, and MyMathLab.
WEB SITE www.pearsonhighered.com/thomas
The Thomas’ Calculus: Early Transcendentals Web site contains the chapter on Second-
Order Differential Equations, including odd-numbered answers, and provides the expanded
historical biographies and essays referenced in the text. Also available is a collection of Maple
and Mathematica modules, the Technology Resource Manuals, and the TechnologyApplica-
tion Projects, which can be used as projects by individual students or groups of students.
MyMathLab Online Course (access code required)
MyMathLab is a text-specific, easily customizable online course that integrates interactive
multimedia instruction with textbook content. MyMathLab gives you the tools you need to
deliver all or a portion of your course online, whether your students are in a lab setting or
working from home.
• Interactive homework exercises, correlated to your textbook at the objective level, are
algorithmically generated for unlimited practice and mastery. Most exercises are free-
response and provide guided solutions, sample problems, and learning aids for extra
help.
• “Getting Ready” chapter includes hundreds of exercises that address prerequisite
skills in algebra and trigonometry. Each student can receive remediation for just those
skills he or she needs help with.
• Personalized Study Plan, generated when students complete a test or quiz, indicates
which topics have been mastered and links to tutorial exercises for topics students have
not mastered.
• Multimedia learning aids, such as video lectures, Java applets, animations, and a
complete multimedia textbook, help students independently improve their understand-
ing and performance.
• Assessment Manager lets you create online homework, quizzes, and tests that are
automatically graded. Select just the right mix of questions from the MyMathLab exer-
cise bank and instructor-created custom exercises.
• Gradebook, designed specifically for mathematics and statistics, automatically tracks
students’ results and gives you control over how to calculate final grades. You can also
add offline (paper-and-pencil) grades to the gradebook.
• MathXL Exercise Builder allows you to create static and algorithmic exercises for
your online assignments. You can use the library of sample exercises as an easy starting
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Preface xv
7001_ThomasET_FM_SE_pi-xvi.qxd 11/3/09 3:18 PM Page xv

Acknowledgments
We would like to express our thanks to the people who made many valuable contributions
to this edition as it developed through its various stages:
Accuracy Checkers
Blaise DeSesa
Paul Lorczak
Kathleen Pellissier
Lauri Semarne
Sarah Streett
Holly Zullo
Reviewers for the Twelfth Edition
Meighan Dillon, Southern Polytechnic State University
Anne Dougherty, University of Colorado
Said Fariabi, San Antonio College
Klaus Fischer, George Mason University
Tim Flood, Pittsburg State University
Rick Ford, California State University—Chico
Robert Gardner, East Tennessee State University
Christopher Heil, Georgia Institute of Technology
Joshua Brandon Holden, Rose-Hulman Institute of Technology
Alexander Hulpke, Colorado State University
Jacqueline Jensen, Sam Houston State University
Jennifer M. Johnson, Princeton University
Hideaki Kaneko, Old Dominion University
Przemo Kranz, University of Mississippi
Xin Li, University of Central Florida
Maura Mast, University of Massachusetts—Boston
Val Mohanakumar, Hillsborough Community College—Dale Mabry Campus
Aaron Montgomery, Central Washington University
Christopher M. Pavone, California State University at Chico
Cynthia Piez, University of Idaho
Brooke Quinlan, Hillsborough Community College—Dale Mabry Campus
Rebecca A. Segal, Virginia Commonwealth University
Andrew V
. Sills, Georgia Southern University
Alex Smith, University of Wisconsin—Eau Claire
Mark A. Smith, Miami University
Donald Solomon, University of Wisconsin—Milwaukee
John Sullivan, Black Hawk College
Maria Terrell, Cornell University
Blake Thornton, Washington University in St. Louis
David Walnut, George Mason University
Adrian Wilson, University of Montevallo
Bobby Winters, Pittsburg State University
Dennis Wortman, University of Massachusetts—Boston
xvi Preface
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1
1
FUNCTIONS
OVERVIEW Functions are fundamental to the study of calculus. In this chapter we review
what functions are and how they are pictured as graphs, how they are combined and trans-
formed, and ways they can be classified. We review the trigonometric functions, and we
discuss misrepresentations that can occur when using calculators and computers to obtain
a function’s graph. We also discuss inverse, exponential, and logarithmic functions. The
real number system, Cartesian coordinates, straight lines, parabolas, and circles are re-
viewed in the Appendices.
1.1
Functions and Their Graphs
Functions are a tool for describing the real world in mathematical terms. A function can be
represented by an equation, a graph, a numerical table, or a verbal description; we will use
all four representations throughout this book. This section reviews these function ideas.
Functions; Domain and Range
The temperature at which water boils depends on the elevation above sea level (the boiling
point drops as you ascend). The interest paid on a cash investment depends on the length
of time the investment is held. The area of a circle depends on the radius of the circle. The
distance an object travels at constant speed along a straight-line path depends on the
elapsed time.
In each case, the value of one variable quantity, say y, depends on the value of another
variable quantity, which we might call x. We say that “y is a function of x” and write this
symbolically as
In this notation, the symbol ƒ represents the function, the letter x is the independent vari-
able representing the input value of ƒ, and y is the dependent variable or output value of
ƒ at x.
y = ƒ(x) (“y equals ƒ of x”).
FPO
DEFINITION A function ƒ from a set D to a set Y is a rule that assigns a unique
(single) element to each element x H D.
ƒsxd H Y
The set D of all possible input values is called the domain of the function. The set of
all values of ƒ(x) as x varies throughout D is called the range of the function. The range
may not include every element in the set Y. The domain and range of a function can be any
sets of objects, but often in calculus they are sets of real numbers interpreted as points of a
coordinate line. (In Chapters 13–16, we will encounter functions for which the elements of
the sets are points in the coordinate plane or in space.)
7001_AWLThomas_ch01p001-057.qxd 10/1/09 2:23 PM Page 1

Often a function is given by a formula that describes how to calculate the output value
from the input variable. For instance, the equation is a rule that calculates the
area A of a circle from its radius r (so r, interpreted as a length, can only be positive in this
formula). When we define a function with a formula and the domain is not
stated explicitly or restricted by context, the domain is assumed to be the largest set of real
x-values for which the formula gives real y-values, the so-called natural domain. If we
want to restrict the domain in some way, we must say so. The domain of is the en-
tire set of real numbers. To restrict the domain of the function to, say, positive values of x,
we would write
Changing the domain to which we apply a formula usually changes the range as well.
The range of is The range of is the set of all numbers ob-
tained by squaring numbers greater than or equal to 2. In set notation (see Appendix 1), the
range is or or
When the range of a function is a set of real numbers, the function is said to be real-
valued. The domains and ranges of many real-valued functions of a real variable are inter-
vals or combinations of intervals. The intervals may be open, closed, or half open, and may
be finite or infinite. The range of a function is not always easy to find.
A function ƒ is like a machine that produces an output value ƒ(x) in its range whenever
we feed it an input value x from its domain (Figure 1.1).The function keys on a calculator give
an example of a function as a machine. For instance, the key on a calculator gives an out-
put value (the square root) whenever you enter a nonnegative number x and press the key.
A function can also be pictured as an arrow diagram (Figure 1.2). Each arrow associ-
ates an element of the domain D with a unique or single element in the set Y. In Figure 1.2, the
arrows indicate that ƒ(a) is associated with a, ƒ(x) is associated with x, and so on. Notice that
a function can have the same value at two different input elements in the domain (as occurs
with ƒ(a) in Figure 1.2), but each input element x is assigned a single output value ƒ(x).
EXAMPLE 1 Let’s verify the natural domains and associated ranges of some simple
functions. The domains in each case are the values of x for which the formula makes sense.
Function Domain (x) Range ( y)
[0, 1]
Solution The formula gives a real y-value for any real number x, so the domain
is The range of is because the square of any real number is
nonnegative and every nonnegative number y is the square of its own square root,
for
The formula gives a real y-value for every x except For consistency
in the rules of arithmetic, we cannot divide any number by zero. The range of the
set of reciprocals of all nonzero real numbers, is the set of all nonzero real numbers, since
That is, for the number is the input assigned to the output
value y.
The formula gives a real y-value only if The range of is
because every nonnegative number is some number’s square root (namely, it is the
square root of its own square).
In the quantity cannot be negative. That is, or
The formula gives real y-values for all The range of is the
set of all nonnegative numbers.
[0, qd,
14 - x
x … 4.
x … 4.
4 - x Ú 0,
4 - x
y = 14 - x,
[0, qd
y = 1x
x Ú 0.
y = 1x
x = 1y
y Z 0
y = 1(1y).
y = 1x,
x = 0.
y = 1x
y Ú 0.
y = A 2yB2
[0, qd
y = x2
s- q, qd.
y = x2
[-1, 1]
y = 21 - x2
[0, qd
s- q, 4]
y = 24 - x
[0, qd
[0, qd
y = 2x
s- q, 0d ´ s0, qd
s - q, 0d ´ s0, qd
y = 1x
[0, qd
s - q, qd
y = x2
2x
2x
[4, qd.
5y ƒ y Ú 46
5x2
ƒ x Ú 26
y = x2
, x Ú 2,
[0, qd.
y = x2
“y = x2
, x 7 0.”
y = x2
y = ƒsxd
A = pr2
2 Chapter 1: Functions
Input
(domain)
Output
(range)
x f(x)
f
FIGURE 1.1 A diagram showing a
function as a kind of machine.
x
a f(a) f(x)
D domain set Y set containing
the range
FIGURE 1.2 A function from a set D to a
set Y assigns a unique element of Y to each
element in D.

The formula gives a real y-value for every x in the closed interval
from to 1. Outside this domain, is negative and its square root is not a real
number. The values of vary from 0 to 1 on the given domain, and the square roots
of these values do the same. The range of is [0, 1].
Graphs of Functions
If ƒ is a function with domain D, its graph consists of the points in the Cartesian plane
whose coordinates are the input-output pairs for ƒ. In set notation, the graph is
The graph of the function is the set of points with coordinates (x, y) for
which Its graph is the straight line sketched in Figure 1.3.
The graph of a function ƒ is a useful picture of its behavior. If (x, y) is a point on the
graph, then is the height of the graph above the point x. The height may be posi-
tive or negative, depending on the sign of (Figure 1.4).
ƒsxd
y = ƒsxd
y = x + 2.
ƒsxd = x + 2
5sx, ƒsxdd ƒ x H D6.
21 - x2
1 - x2
1 - x2
-1
y = 21 - x2
x
y
–2 0
2
y x 2
FIGURE 1.3 The graph of
is the set of points (x, y) for which y has
the value x + 2.
ƒsxd = x + 2
y
x
0 1 2
x
f(x)
(x, y)
f(1)
f(2)
FIGURE 1.4 If (x, y) lies on the graph of
ƒ, then the value is the height of
the graph above the point x (or below x if
ƒ(x) is negative).
y = ƒsxd
EXAMPLE 2 Graph the function over the interval
Solution Make a table of xy-pairs that satisfy the equation . Plot the points (x, y)
whose coordinates appear in the table, and draw a smooth curve (labeled with its equation)
through the plotted points (see Figure 1.5).
How do we know that the graph of doesn’t look like one of these curves?
y = x2
y = x2
[-2, 2].
y = x2
x
4
1
0 0
1 1
2 4
9
4
3
2
-1
-2
y x 2
y x2
?
x
y
y x2
?
x
y
0 1 2
–1
–2
1
2
3
4
(–2, 4)
(–1, 1) (1, 1)
(2, 4)
⎛
⎝
⎛
⎝
3
2
9
4
,
x
y
y x2
FIGURE 1.5 Graph of the function in
Example 2.

To find out, we could plot more points. But how would we then connect them? The
basic question still remains: How do we know for sure what the graph looks like be-
tween the points we plot? Calculus answers this question, as we will see in Chapter 4.
Meanwhile we will have to settle for plotting points and connecting them as best
we can.
Representing a Function Numerically
We have seen how a function may be represented algebraically by a formula (the area
function) and visually by a graph (Example 2). Another way to represent a function is
numerically, through a table of values. Numerical representations are often used by engi-
neers and scientists. From an appropriate table of values, a graph of the function can be
obtained using the method illustrated in Example 2, possibly with the aid of a computer.
The graph consisting of only the points in the table is called a scatterplot.
EXAMPLE 3 Musical notes are pressure waves in the air. The data in Table 1.1 give
recorded pressure displacement versus time in seconds of a musical note produced by a
tuning fork. The table provides a representation of the pressure function over time. If we
first make a scatterplot and then connect approximately the data points (t, p) from the
table, we obtain the graph shown in Figure 1.6.
The Vertical Line Test for a Function
Not every curve in the coordinate plane can be the graph of a function. A function ƒ can
have only one value for each x in its domain, so no vertical line can intersect the graph
of a function more than once. If a is in the domain of the function ƒ, then the vertical line
will intersect the graph of ƒ at the single point .
A circle cannot be the graph of a function since some vertical lines intersect the circle
twice. The circle in Figure 1.7a, however, does contain the graphs of two functions of x:
the upper semicircle defined by the function and the lower semicircle
defined by the function (Figures 1.7b and 1.7c).
g(x) = - 21 - x2
ƒ(x) = 21 - x2
(a, ƒ(a))
x = a
ƒ(x)
TABLE 1.1 Tuning fork data
Time Pressure Time Pressure
0.00091 0.00362 0.217
0.00108 0.200 0.00379 0.480
0.00125 0.480 0.00398 0.681
0.00144 0.693 0.00416 0.810
0.00162 0.816 0.00435 0.827
0.00180 0.844 0.00453 0.749
0.00198 0.771 0.00471 0.581
0.00216 0.603 0.00489 0.346
0.00234 0.368 0.00507 0.077
0.00253 0.099 0.00525
0.00271 0.00543
0.00289 0.00562
0.00307 0.00579
0.00325 0.00598
0.00344 -0.041
-0.035
-0.248
-0.248
-0.348
-0.354
-0.309
-0.320
-0.141
-0.164
-0.080
–0.6
–0.4
–0.2
0.2
0.4
0.6
0.8
1.0
t (sec)
p (pressure)
0.001 0.002 0.004 0.006
0.003 0.005
Data
FIGURE 1.6 A smooth curve through the plotted points
gives a graph of the pressure function represented by
Table 1.1 (Example 3).

–2 –1 0 1 2
1
2
x
y
y –x
y x2
y 1
y f(x)
FIGURE 1.9 To graph the
function shown here,
we apply different formulas to
different parts of its domain
(Example 4).
y = ƒsxd
x
y x
y x
y –x
y
–3 –2 –1 0 1 2 3
1
2
3
FIGURE 1.8 The absolute value
function has domain
and range [0, qd.
s- q, qd
–1 1
0
x
y
(a) x2
y2
1
–1 1
0
x
y
–1 1
0
x
y
(b) y 1 x2 (c) y –1 x2
FIGURE 1.7 (a) The circle is not the graph of a function; it fails the vertical line test. (b) The upper
semicircle is the graph of a function (c) The lower semicircle is the graph of a
function gsxd = - 21 - x2
.
ƒsxd = 21 - x2
.
Piecewise-Defined Functions
Sometimes a function is described by using different formulas on different parts of its
domain. One example is the absolute value function
whose graph is given in Figure 1.8. The right-hand side of the equation means that the
function equals x if , and equals if Here are some other examples.
EXAMPLE 4 The function
is defined on the entire real line but has values given by different formulas depending on
the position of x. The values of ƒ are given by when when
and when The function, however, is just one function whose
domain is the entire set of real numbers (Figure 1.9).
EXAMPLE 5 The function whose value at any number x is the greatest integer less
than or equal to x is called the greatest integer function or the integer floor function.
It is denoted . Figure 1.10 shows the graph. Observe that
EXAMPLE 6 The function whose value at any number x is the smallest integer greater
than or equal to x is called the least integer function or the integer ceiling function. It is
denoted Figure 1.11 shows the graph. For positive values of x, this function might
represent, for example, the cost of parking x hours in a parking lot which charges $1 for
each hour or part of an hour.
x= .
:2.4; = 2, :1.9; = 1, :0; = 0, : -1.2; = -2,
:2; = 2, :0.2; = 0, : -0.3; = -1 : -2; = -2.
:x;
x 7 1.
y = 1
0 … x … 1,
x 6 0, y = x2
y = -x
ƒsxd = •
-x, x 6 0
x2
, 0 … x … 1
1, x 7 1
x 6 0.
-x
x Ú 0
ƒ x ƒ = e
x, x Ú 0
-x, x 6 0,
1
–2
2
3
–2 –1 1 2 3
y x
y ⎣x⎦
x
y
FIGURE 1.10 The graph of the
greatest integer function
lies on or below the line so
it provides an integer floor for x
(Example 5).
y = x,
y = :x;

The names even and odd come from powers of x. If y is an even power of x, as in
or it is an even function of x because and If y is
an odd power of x, as in or it is an odd function of x because
and
The graph of an even function is symmetric about the y-axis. Since a
point (x, y) lies on the graph if and only if the point lies on the graph (Figure 1.12a).
A reflection across the y-axis leaves the graph unchanged.
The graph of an odd function is symmetric about the origin. Since a
point (x, y) lies on the graph if and only if the point lies on the graph (Figure 1.12b).
Equivalently, a graph is symmetric about the origin if a rotation of 180° about the origin
leaves the graph unchanged. Notice that the definitions imply that both x and must be
in the domain of ƒ.
EXAMPLE 8
Even function: for all x; symmetry about y-axis.
Even function: for all x; symmetry about y-axis
(Figure 1.13a).
Odd function: for all x; symmetry about the origin.
Not odd: but The two are not
equal.
Not even: for all (Figure 1.13b).
x Z 0
s -xd + 1 Z x + 1
-ƒsxd = -x - 1.
ƒs-xd = -x + 1,
ƒsxd = x + 1
s-xd = -x
ƒsxd = x
s-xd2
+ 1 = x2
+ 1
ƒsxd = x2
+ 1
s-xd2
= x2
ƒsxd = x2
-x
s-x, -yd
ƒs-xd = -ƒsxd,
s -x, yd
ƒs-xd = ƒsxd,
s-xd3
= -x3
.
s-xd1
= -x
y = x3
,
y = x
s-xd4
= x4
.
s-xd2
= x2
y = x4
,
y = x2
Increasing and Decreasing Functions
If the graph of a function climbs or rises as you move from left to right, we say that the
function is increasing. If the graph descends or falls as you move from left to right, the
function is decreasing.
DEFINITIONS Let ƒ be a function defined on an interval I and let and be
any two points in I.
1. If whenever then ƒ is said to be increasing on I.
2. If whenever then ƒ is said to be decreasing on I.
x1 6 x2,
ƒsx2d 6 ƒsx1d
x1 6 x2,
ƒsx2) 7 ƒsx1d
x2
x1
x
y
1
–1
–2 2 3
–2
–1
1
2
3
y x
y ⎡x⎤
FIGURE 1.11 The graph of the
least integer function
lies on or above the line
so it provides an integer ceiling
for x (Example 6).
y = x,
y = x=
DEFINITIONS A function is an
for every x in the function’s domain.
even function of x if ƒs-xd = ƒsxd,
odd function of x if ƒs-xd = -ƒsxd,
y = ƒsxd
It is important to realize that the definitions of increasing and decreasing functions
must be satisfied for every pair of points and in I with Because we use the
inequality to compare the function values, instead of it is sometimes said that ƒ is
strictly increasing or decreasing on I. The interval I may be finite (also called bounded) or
infinite (unbounded) and by definition never consists of a single point (Appendix 1).
EXAMPLE 7 The function graphed in Figure 1.9 is decreasing on and in-
creasing on [0, 1]. The function is neither increasing nor decreasing on the interval
because of the strict inequalities used to compare the function values in the definitions.
Even Functions and Odd Functions: Symmetry
The graphs of even and odd functions have characteristic symmetry properties.
[1, qd
s- q, 0]
… ,
6
x1 6 x2.
x2
x1
(a)
(b)
0
x
y
y x2
(x, y)
(–x, y)
0
x
y
y x3
(x, y)
(–x, –y)
FIGURE 1.12 (a) The graph of
(an even function) is symmetric about the
y-axis. (b) The graph of (an odd
function) is symmetric about the origin.
y = x3
y = x2

(a) (b)
x
y
0
1
y x2
1
y x2
x
y
0
–1
1
y x 1
y x
FIGURE 1.13 (a) When we add the constant term 1 to the function
the resulting function is still even and its graph is
still symmetric about the y-axis. (b) When we add the constant term 1 to
the function the resulting function is no longer odd.
The symmetry about the origin is lost (Example 8).
y = x + 1
y = x,
y = x2
+ 1
y = x2
,
Common Functions
A variety of important types of functions are frequently encountered in calculus. We iden-
tify and briefly describe them here.
Linear Functions A function of the form for constants m and b, is
called a linear function. Figure 1.14a shows an array of lines where
so these lines pass through the origin. The function where and is
called the identity function. Constant functions result when the slope (Figure
1.14b). A linear function with positive slope whose graph passes through the origin is
called a proportionality relationship.
m = 0
b = 0
m = 1
ƒsxd = x
b = 0,
ƒsxd = mx
ƒsxd = mx + b,
x
y
0 1 2
1
2 y
3
2
(b)
FIGURE 1.14 (a) Lines through the origin with slope m. (b) A constant function
with slope m = 0.
0
x
y
m –3 m 2
m 1
m –1
y –3x
y –x
y 2x
y x
y x
1
2
m
1
2
(a)
DEFINITION Two variables y and x are proportional (to one another) if one is
always a constant multiple of the other; that is, if for some nonzero
constant k.
y = kx
If the variable y is proportional to the reciprocal then sometimes it is said that y is
inversely proportional to x (because is the multiplicative inverse of x).
Power Functions A function where a is a constant, is called a power func-
tion. There are several important cases to consider.
ƒsxd = xa
,
1x
1x,

(b)
The graphs of the functions and are shown in
Figure 1.16. Both functions are defined for all (you can never divide by zero). The
graph of is the hyperbola , which approaches the coordinate axes far from
the origin. The graph of also approaches the coordinate axes. The graph of the
function ƒ is symmetric about the origin; ƒ is decreasing on the intervals and
. The graph of the function g is symmetric about the y-axis; g is increasing on
and decreasing on .
s0, q)
s- q, 0)
s0, q)
s - q, 0)
y = 1x2
xy = 1
y = 1x
x Z 0
gsxd = x-2
= 1x2
ƒsxd = x-1
= 1x
a = -1 or a = -2.
–1 0 1
–1
1
x
y y x2
–1 1
0
–1
1
x
y y x
–1 1
0
–1
1
x
y y x3
–1 0 1
–1
1
x
y y x4
–1 0 1
–1
1
x
y y x5
FIGURE 1.15 Graphs of defined for - q 6 x 6 q .
ƒsxd = xn
, n = 1, 2, 3, 4, 5,
(a)
The graphs of for 2, 3, 4, 5, are displayed in Figure 1.15. These func-
tions are defined for all real values of x. Notice that as the power n gets larger, the curves
tend to flatten toward the x-axis on the interval and also rise more steeply for
Each curve passes through the point (1, 1) and through the origin. The graphs of
functions with even powers are symmetric about the y-axis; those with odd powers are
symmetric about the origin. The even-powered functions are decreasing on the interval
and increasing on ; the odd-powered functions are increasing over the entire
real line .
s- q, q)
[0, qd
s- q, 0]
ƒ x ƒ 7 1.
s -1, 1d,
n = 1,
ƒsxd = xn
,
a = n, a positive integer.
x
y
x
y
0
1
1
0
1
1
y
1
x y
1
x2
Domain: x 0
Range: y 0
Domain: x 0
Range: y 0
(a) (b)
FIGURE 1.16 Graphs of the power functions for part (a)
and for part (b) .
a = -2
a = -1
ƒsxd = xa
(c)
The functions and are the square root and cube
root functions, respectively. The domain of the square root function is but the
cube root function is defined for all real x. Their graphs are displayed in Figure 1.17
along with the graphs of and (Recall that and
)
Polynomials A function p is a polynomial if
where n is a nonnegative integer and the numbers are real constants
(called the coefficients of the polynomial). All polynomials have domain If the
s- q, qd.
a0, a1, a2, Á , an
psxd = anxn
+ an-1xn-1
+ Á + a1x + a0
x23
= sx13
d2
.
x32
= sx12
d3
y = x23
.
y = x32
[0, qd,
gsxd = x13
= 2
3
x
ƒsxd = x12
= 2x
a =
1
2
,
1
3
,
3
2
, and
2
3
.

y
x
0
1
1
y x32
Domain:
Range:
0 x
0 y
y
x
Domain:
Range:
– x
0 y
0
1
1
y x23
x
y
0 1
1
Domain:
Range:
0 x
0 y
y x
x
y
Domain:
Range:
– x
– y
1
1
0
3
y x
FIGURE 1.17 Graphs of the power functions for and
2
3
.
a =
1
2
,
1
3
,
3
2
,
ƒsxd = xa
leading coefficient and then n is called the degree of the polynomial. Linear
functions with are polynomials of degree 1. Polynomials of degree 2, usually written
as are called quadratic functions. Likewise, cubic functions are
polynomials of degree 3. Figure 1.18 shows the graphs of
three polynomials. Techniques to graph polynomials are studied in Chapter 4.
psxd = ax3
+ bx2
+ cx + d
psxd = ax2
+ bx + c,
m Z 0
n 7 0,
an Z 0
x
y
0
y 2x
x3
3
x2
2
1
3
(a)
y
x
–1 1 2
2
–2
–4
–6
–8
–10
–12
y 8x4
14x3
9x2
11x 1
(b)
–1 0 1 2
–16
16
x
y
y (x 2)4
(x 1)3
(x 1)
(c)
–2
–4 2 4
–4
–2
2
4
FIGURE 1.18 Graphs of three polynomial functions.
(a) (b) (c)
2 4
–4 –2
–2
2
4
–4
x
y
y
2x2
3
7x 4
0
–2
–4
–6
–8
2
–2
–4 4 6
2
4
6
8
x
y
y
11x 2
2x3
1
–5 0
1
2
–1
5 10
–2
x
y
Line y
5
3
y
5x2
8x 3
3x2
2
NOT TO SCALE
FIGURE 1.19 Graphs of three rational functions. The straight red lines are called asymptotes and are not part
of the graph.
Rational Functions A rational function is a quotient or ratio where p
and q are polynomials. The domain of a rational function is the set of all real x for which
The graphs of several rational functions are shown in Figure 1.19.
qsxd Z 0.
ƒ(x) = p(x)q(x),

Trigonometric Functions The six basic trigonometric functions are reviewed in Section 1.3.
The graphs of the sine and cosine functions are shown in Figure 1.21.
Exponential Functions Functions of the form where the base is a
positive constant and are called exponential functions. All exponential functions
have domain and range , so an exponential function never assumes the
value 0. We discuss exponential functions in Section 1.5. The graphs of some exponential
functions are shown in Figure 1.22.
s0, qd
s - q, qd
a Z 1,
a 7 0
ƒsxd = ax
,
Algebraic Functions Any function constructed from polynomials using algebraic opera-
tions (addition, subtraction, multiplication, division, and taking roots) lies within the class
of algebraic functions. All rational functions are algebraic, but also included are more
complicated functions (such as those satisfying an equation like
studied in Section 3.7). Figure 1.20 displays the graphs of three algebraic functions.
y3
- 9xy + x3
= 0,
(a)
4
–1
–3
–2
–1
1
2
3
4
x
y y x1/3
(x 4)
(b)
0
y
x
y (x2
1)2/3
3
4
(c)
1
0
–1
1
x
y
5
7
y x(1 x)2/5
FIGURE 1.20 Graphs of three algebraic functions.
y
x
1
–1

2

3
(a) f(x) sin x
0
y
x
1
–1

2
3
2 2
(b) f(x) cos x
0

2
–
–
5
FIGURE 1.21 Graphs of the sine and cosine functions.
(a) (b)
y 2–x
y 3–x
y 10–x
–0.5
–1 0 0.5 1
2
4
6
8
10
12
y
x
y 2x
y 3x
y 10x
–0.5
–1 0 0.5 1
2
4
6
8
10
12
y
x
FIGURE 1.22 Graphs of exponential functions.

Logarithmic Functions These are the functions where the base is
a positive constant. They are the inverse functions of the exponential functions, and we
discuss these functions in Section 1.6. Figure 1.23 shows the graphs of four logarithmic
functions with various bases. In each case the domain is and the range is
s- q, qd.
s0, q d
a Z 1
ƒsxd = loga x,
–1 1
0
1
x
y
FIGURE 1.24 Graph of a catenary or
hanging cable. (The Latin word catena
means “chain.”)
1
–1
1
0
x
y
y log3x
y log10 x
y log2x
y log5x
FIGURE 1.23 Graphs of four logarithmic
functions.
Transcendental Functions These are functions that are not algebraic. They include the
trigonometric, inverse trigonometric, exponential, and logarithmic functions, and many
other functions as well. A particular example of a transcendental function is a catenary.
Its graph has the shape of a cable, like a telephone line or electric cable, strung from one
support to another and hanging freely under its own weight (Figure 1.24). The function
defining the graph is discussed in Section 7.3.
Exercises 1.1
Functions
In Exercises 1–6, find the domain and range of each function.
1. 2.
3. 4.
5. 6.
In Exercises 7 and 8, which of the graphs are graphs of functions of x,
and which are not? Give reasons for your answers.
7. a. b.
x
y
0
x
y
0
G(t) =
2
t2
- 16
ƒstd =
4
3 - t
g(x) = 2x2
- 3x
F(x) = 25x + 10
ƒsxd = 1 - 2x
ƒsxd = 1 + x2
8. a. b.
Finding Formulas for Functions
9. Express the area and perimeter of an equilateral triangle as a
function of the triangle’s side length x.
10. Express the side length of a square as a function of the length d of
the square’s diagonal. Then express the area as a function of the
diagonal length.
11. Express the edge length of a cube as a function of the cube’s diag-
onal length d. Then express the surface area and volume of the
cube as a function of the diagonal length.
x
y
0
x
y
0

12. A point P in the first quadrant lies on the graph of the function
Express the coordinates of P as functions of the
slope of the line joining P to the origin.
13. Consider the point lying on the graph of the line
Let L be the distance from the point to the
origin Write L as a function of x.
14. Consider the point lying on the graph of Let
L be the distance between the points and Write L as a
function of y.
Functions and Graphs
Find the domain and graph the functions in Exercises 15–20.
15. 16.
17. 18.
19. 20.
21. Find the domain of
22. Find the range of
23. Graph the following equations and explain why they are not
graphs of functions of x.
a. b.
24. Graph the following equations and explain why they are not
graphs of functions of x.
a. b.
Piecewise-Defined Functions
Graph the functions in Exercises 25–28.
25.
26.
27.
28.
Find a formula for each function graphed in Exercises 29–32.
29. a. b.
30. a. b.
–1
x
y
3
2
1
2
1
–2
–3
–1
(2, –1)
x
y
5
2
2
(2, 1)
t
y
0
2
4
1 2 3
x
y
0
1
2
(1, 1)
Gsxd = e
1x, x 6 0
x, 0 … x
Fsxd = e
4 - x2
, x … 1
x2
+ 2x, x 7 1
gsxd = e
1 - x, 0 … x … 1
2 - x, 1 6 x … 2
ƒsxd = e
x, 0 … x … 1
2 - x, 1 6 x … 2
ƒ x + y ƒ = 1
ƒ x ƒ + ƒ y ƒ = 1
y2
= x2
ƒ y ƒ = x
y = 2 +
x2
x2
+ 4
.
y =
x + 3
4 - 2x2
- 9
.
Gstd = 1ƒ t ƒ
Fstd = tƒ t ƒ
gsxd = 2-x
gsxd = 2ƒ x ƒ
ƒsxd = 1 - 2x - x2
ƒsxd = 5 - 2x
(4, 0).
(x, y)
2x - 3.
y =
(x, y)
(0, 0).
(x, y)
2x + 4y = 5.
(x, y)
ƒsxd = 2x.
31. a. b.
32. a. b.
The Greatest and Least Integer Functions
33. For what values of x is
a. b.
34. What real numbers x satisfy the equation
35. Does for all real x? Give reasons for your answer.
36. Graph the function
Why is ƒ(x) called the integer part of x?
Increasing and Decreasing Functions
Graph the functions in Exercises 37–46. What symmetries, if any, do
the graphs have? Specify the intervals over which the function is in-
creasing and the intervals where it is decreasing.
37. 38.
39. 40.
41. 42.
43. 44.
45. 46.
Even and Odd Functions
In Exercises 47–58, say whether the function is even, odd, or neither.
Give reasons for your answer.
47. 48.
49. 50.
51. 52.
53. 54.
55. 56.
57. 58.
Theory and Examples
59. The variable s is proportional to t, and when
Determine t when s = 60.
t = 75.
s = 25
hstd = 2ƒ t ƒ + 1
hstd = 2t + 1
hstd = ƒ t3 ƒ
hstd =
1
t - 1
gsxd =
x
x2
- 1
gsxd =
1
x2
- 1
gsxd = x4
+ 3x2
- 1
gsxd = x3
+ x
ƒsxd = x2
+ x
ƒsxd = x2
+ 1
ƒsxd = x-5
ƒsxd = 3
y = s-xd23
y = -x32
y = -42x
y = x3
8
y = 2-x
y = 2ƒ x ƒ
y =
1
ƒ x ƒ
y = -
1
x
y = -
1
x2
y = -x3
ƒsxd = e
:x;, x Ú 0
x=, x 6 0.
-x= = - :x;
:x; = x= ?
x= = 0?
:x; = 0?
t
y
0
A
T
–A
T
2
3T
2
2T
x
y
0
1
T
T
2
(T, 1)
x
y
1
2
(–2, –1) (3, –1)
(1, –1)
x
y
3
1
(–1, 1) (1, 1)

60. Kinetic energy The kinetic energy K of a mass is proportional
to the square of its velocity If joules when
what is K when
61. The variables r and s are inversely proportional, and when
Determine s when
62. Boyle’s Law Boyle’s Law says that the volume V of a gas at con-
stant temperature increases whenever the pressure P decreases, so
that V and P are inversely proportional. If when
then what is V when
63. A box with an open top is to be constructed from a rectangular
piece of cardboard with dimensions 14 in. by 22 in. by cutting out
equal squares of side x at each corner and then folding up the
sides as in the figure. Express the volume V of the box as a func-
tion of x.
64. The accompanying figure shows a rectangle inscribed in an isosce-
les right triangle whose hypotenuse is 2 units long.
a. Express the y-coordinate of P in terms of x. (You might start
by writing an equation for the line AB.)
b. Express the area of the rectangle in terms of x.
In Exercises 65 and 66, match each equation with its graph. Do not
use a graphing device, and give reasons for your answer.
65. a. b. c.
x
y
f
g
h
0
y = x10
y = x7
y = x4
x
y
–1 0 1
x
A
B
P(x, ?)
x
x
x
x
x
x
x
x
22
14
P = 23.4 lbsin2
?
V = 1000 in3
,
P = 14.7 lbsin2
r = 10.
s = 4.
r = 6
y = 10 msec?
y = 18 msec,
K = 12,960
y.
66. a. b. c.
67. a. Graph the functions and to-
gether to identify the values of x for which
b. Confirm your findings in part (a) algebraically.
68. a. Graph the functions and
together to identify the values of x for which
b. Confirm your findings in part (a) algebraically.
69. For a curve to be symmetric about the x-axis, the point (x, y) must
lie on the curve if and only if the point lies on the curve.
Explain why a curve that is symmetric about the x-axis is not the
graph of a function, unless the function is
70. Three hundred books sell for $40 each, resulting in a revenue of
For each $5 increase in the price, 25
fewer books are sold. Write the revenue R as a function of the
number x of $5 increases.
71. A pen in the shape of an isosceles right triangle with legs of length
x ft and hypotenuse of length h ft is to be built. If fencing costs
$5/ft for the legs and $10/ft for the hypotenuse, write the total cost
C of construction as a function of h.
72. Industrial costs A power plant sits next to a river where the
river is 800 ft wide. To lay a new cable from the plant to a location
in the city 2 mi downstream on the opposite side costs $180 per
foot across the river and $100 per foot along the land.
a. Suppose that the cable goes from the plant to a point Q on the
opposite side that is x ft from the point P directly opposite the
plant. Write a function C(x) that gives the cost of laying the
cable in terms of the distance x.
b. Generate a table of values to determine if the least expensive
location for point Q is less than 2000 ft or greater than 2000 ft
from point P.
x Q
P
Power plant
City
800 ft
2 mi
NOT TO SCALE
(300)($40) = $12,000.
y = 0.
sx, -yd
3
x - 1
6
2
x + 1
.
gsxd = 2sx + 1d
ƒsxd = 3sx - 1d
x
2
7 1 +
4
x .
gsxd = 1 + s4xd
ƒsxd = x2
x
y
f
h
g
0
y = x5
y = 5x
y = 5x
T
T

1.2
Combining Functions; Shifting and Scaling Graphs
In this section we look at the main ways functions are combined or transformed to form
new functions.
Sums, Differences, Products, and Quotients
Like numbers, functions can be added, subtracted, multiplied, and divided (except where
the denominator is zero) to produce new functions. If ƒ and g are functions, then for every
x that belongs to the domains of both ƒ and g (that is, for ), we define
functions and ƒg by the formulas
Notice that the sign on the left-hand side of the first equation represents the operation of
addition of functions, whereas the on the right-hand side of the equation means addition
of the real numbers ƒ(x) and g(x).
At any point of at which we can also define the function
by the formula
Functions can also be multiplied by constants: If c is a real number, then the function
cƒ is defined for all x in the domain of ƒ by
EXAMPLE 1 The functions defined by the formulas
have domains and The points common to these do-
mains are the points
The following table summarizes the formulas and domains for the various algebraic com-
binations of the two functions. We also write for the product function ƒg.
Function Formula Domain
[0, 1]
[0, 1]
[0, 1]
[0, 1)
(0, 1]
The graph of the function is obtained from the graphs of ƒ and g by adding the
corresponding y-coordinates ƒ(x) and g(x) at each point as in Figure
1.25. The graphs of and from Example 1 are shown in Figure 1.26.
ƒ # g
ƒ + g
x H Dsƒd ¨ Dsgd,
ƒ + g
sx = 0 excludedd
g
ƒ
sxd =
gsxd
ƒsxd
=
A
1 - x
x
gƒ
sx = 1 excludedd
ƒ
g sxd =
ƒsxd
gsxd
=
A
x
1 - x
ƒg
sƒ # gdsxd = ƒsxdgsxd = 2xs1 - xd
ƒ # g
sg - ƒdsxd = 21 - x - 2x
g - ƒ
sƒ - gdsxd = 2x - 21 - x
ƒ - g
[0, 1] = Dsƒd ¨ Dsgd
sƒ + gdsxd = 2x + 21 - x
ƒ + g
ƒ # g
[0, qd ¨ s - q, 1] = [0, 1].
Dsgd = s- q, 1].
Dsƒd = [0, qd
ƒsxd = 2x and gsxd = 21 - x
scƒdsxd = cƒsxd.
a
ƒ
gbsxd =
ƒsxd
gsxd
swhere gsxd Z 0d.
ƒg
gsxd Z 0,
Dsƒd ¨ Dsgd
+
+
sƒgdsxd = ƒsxdgsxd.
sƒ - gdsxd = ƒsxd - gsxd.
sƒ + gdsxd = ƒsxd + gsxd.
ƒ + g, ƒ - g,
x H Dsƒd ¨ Dsgd

y ( f g)(x)
y g(x)
y f(x) f(a)
g(a)
f(a) g(a)
a
2
0
4
6
8
y
x
FIGURE 1.25 Graphical addition of two
functions.
5
1
5
2
5
3
5
4 1
0
1
x
y
2
1
g(x) 1 x f(x) x
y f g
y f • g
FIGURE 1.26 The domain of the function is
the intersection of the domains of ƒ and g, the
interval [0, 1] on the x-axis where these domains
overlap. This interval is also the domain of the
function (Example 1).
ƒ # g
ƒ + g
Composite Functions
Composition is another method for combining functions.
DEFINITION If ƒ and g are functions, the composite function (“ƒ com-
posed with g”) is defined by
The domain of consists of the numbers x in the domain of g for which g(x)
lies in the domain of ƒ.
ƒ g
sƒ gdsxd = ƒsgsxdd.
ƒ g
The definition implies that can be formed when the range of g lies in the
domain of ƒ. To find first find g(x) and second find ƒ(g(x)). Figure 1.27 pic-
tures as a machine diagram and Figure 1.28 shows the composite as an arrow di-
agram.
ƒ g
sƒ gdsxd,
ƒ g
x g f f(g(x))
g(x)
x
f(g(x))
g(x)
g
f
f g
FIGURE 1.27 Two functions can be composed at
x whenever the value of one function at x lies in the
domain of the other. The composite is denoted by
ƒ g. FIGURE 1.28 Arrow diagram for ƒ g.
To evaluate the composite function (when defined), we find ƒ(x) first and then
g(ƒ(x)). The domain of is the set of numbers x in the domain of ƒ such that ƒ(x) lies
in the domain of g.
The functions and are usually quite different.
g ƒ
ƒ g
g ƒ
g ƒ

EXAMPLE 2 If and find
(a) (b) (c) (d)
Solution
Composite Domain
(a)
(b)
(c)
(d)
To see why the domain of notice that is defined for all
real x but belongs to the domain of ƒ only if that is to say, when
Notice that if and then However,
the domain of is not since requires
Shifting a Graph of a Function
A common way to obtain a new function from an existing one is by adding a constant to
each output of the existing function, or to its input variable. The graph of the new function
is the graph of the original function shifted vertically or horizontally, as follows.
x Ú 0.
2x
s- q, qd,
[0, qd,
ƒ g
sƒ gdsxd = A 2xB2
= x.
gsxd = 2x,
ƒsxd = x2
x Ú -1.
x + 1 Ú 0,
gsxd = x + 1
ƒ g is [-1, qd,
s- q, qd
sg gdsxd = gsgsxdd = gsxd + 1 = sx + 1d + 1 = x + 2
[0, qd
sƒ ƒdsxd = ƒsƒsxdd = 2ƒsxd = 21x = x14
[0, qd
sg ƒdsxd = gsƒsxdd = ƒsxd + 1 = 2x + 1
[-1, qd
sƒ gdsxd = ƒsgsxdd = 2gsxd = 2x + 1
sg gdsxd.
sƒ ƒdsxd
sg ƒdsxd
sƒ gdsxd
gsxd = x + 1,
ƒsxd = 2x
Shift Formulas
Vertical Shifts
Shifts the graph of ƒ up
Shifts it down
Horizontal Shifts
Shifts the graph of ƒ left
Shifts it right ƒ h ƒ units if h 6 0
h units if h 7 0
y = ƒsx + hd
ƒ k ƒ units if k 6 0
k units if k 7 0
y = ƒsxd + k
x
y
2
1
2
2 units
1 unit
–2
–2
–1
0
y x2
2
y x2
y x2
1
y x2
2
FIGURE 1.29 To shift the graph
of up (or down), we add
positive (or negative) constants to
the formula for ƒ (Examples 3a
and b).
ƒsxd = x2
EXAMPLE 3
(a) Adding 1 to the right-hand side of the formula to get shifts the
graph up 1 unit (Figure 1.29).
(b) Adding to the right-hand side of the formula to get shifts the
graph down 2 units (Figure 1.29).
(c) Adding 3 to x in to get shifts the graph 3 units to the left (Figure
1.30).
(d) Adding to x in and then adding to the result, gives
and shifts the graph 2 units to the right and 1 unit down (Figure 1.31).
Scaling and Reflecting a Graph of a Function
To scale the graph of a function is to stretch or compress it, vertically or hori-
zontally. This is accomplished by multiplying the function ƒ, or the independent variable x,
by an appropriate constant c. Reflections across the coordinate axes are special cases
where c = -1.
y = ƒsxd
y = ƒ x - 2 ƒ - 1
-1
y = ƒ x ƒ,
-2
y = sx + 3d2
y = x2
y = x2
- 2
y = x2
-2
y = x2
+ 1
y = x2

x
y
0
–3 2
1
1
y (x 2)2
y x2
y (x 3)2
Add a positive
constant to x.
Add a negative
constant to x.
–4 –2 2 4 6
–1
1
4
x
y
y x – 2 – 1
FIGURE 1.30 To shift the graph of to the
left, we add a positive constant to x (Example 3c).
To shift the graph to the right, we add a negative
constant to x.
y = x2
FIGURE 1.31 Shifting the graph of
units to the right and 1 unit
down (Example 3d).
y = ƒ x ƒ 2
EXAMPLE 4 Here we scale and reflect the graph of
(a) Vertical: Multiplying the right-hand side of by 3 to get stretches
the graph vertically by a factor of 3, whereas multiplying by compresses the
graph by a factor of 3 (Figure 1.32).
(b) Horizontal: The graph of is a horizontal compression of the graph of
by a factor of 3, and is a horizontal stretching by a factor of 3
(Figure 1.33). Note that so a horizontal compression may cor-
respond to a vertical stretching by a different scaling factor. Likewise, a horizontal
stretching may correspond to a vertical compression by a different scaling factor.
(c) Reflection: The graph of is a reflection of across the x-axis, and
is a reflection across the y-axis (Figure 1.34).
y = 2-x
y = 2x
y = - 2x
y = 23x = 232x
y = 2x3
y = 2x
y = 23x
13
y = 32x
y = 2x
y = 2x.
Vertical and Horizontal Scaling and Reflecting Formulas
For , the graph is scaled:
Stretches the graph of ƒ vertically by a factor of c.
Compresses the graph of ƒ vertically by a factor of c.
Compresses the graph of ƒ horizontally by a factor of c.
Stretches the graph of ƒ horizontally by a factor of c.
For , the graph is reflected:
Reflects the graph of ƒ across the x-axis.
Reflects the graph of ƒ across the y-axis.
y = ƒs-xd
y = -ƒsxd
c = -1
y = ƒsxcd
y = ƒscxd
y =
1
c ƒsxd
y = cƒsxd
c 7 1
–1 1
0 2 3 4
1
2
3
4
5
x
y
y x
y x
y 3x
3
1
stretch
compress
–1 0 1 2 3 4
1
2
3
4
x
y
y 3x
y x3
y x
compress
stretch –3 –2 –1 1 2 3
–1
1
x
y
y x
y –x
y –x
FIGURE 1.32 Vertically stretching and
compressing the graph by a
factor of 3 (Example 4a).
y = 1x
FIGURE 1.33 Horizontally stretching and
compressing the graph by a factor of
3 (Example 4b).
y = 1x
FIGURE 1.34 Reflections of the graph
across the coordinate axes
(Example 4c).
y = 1x

EXAMPLE 5 Given the function (Figure 1.35a), find formulas to
(a) compress the graph horizontally by a factor of 2 followed by a reflection across the
y-axis (Figure 1.35b).
(b) compress the graph vertically by a factor of 2 followed by a reflection across the x-axis
(Figure 1.35c).
ƒsxd = x4
- 4x3
+ 10
Solution
(a) We multiply x by 2 to get the horizontal compression, and by to give reflection
across the y-axis. The formula is obtained by substituting for x in the right-hand
side of the equation for ƒ:
(b) The formula is
Ellipses
Although they are not the graphs of functions, circles can be stretched horizontally or ver-
tically in the same way as the graphs of functions. The standard equation for a circle of
radius r centered at the origin is
Substituting cx for x in the standard equation for a circle (Figure 1.36a) gives
(1)
c2
x2
+ y2
= r2
.
x2
+ y2
= r2
.
y = -
1
2
ƒsxd = -
1
2
x4
+ 2x3
- 5.
= 16x4
+ 32x3
+ 10.
y = ƒs-2xd = s-2xd4
- 4s -2xd3
+ 10
-2x
-1
–1 0 1 2 3 4
–20
–10
10
20
x
y
f(x) x4
4x3
10
(a)
–2 –1 0 1
–20
–10
10
20
x
y
(b)
y 16x4
32x3
10
–1 0 1 2 3 4
–10
10
x
y
y – x4
2x3
5
1
2
(c)
FIGURE 1.35 (a) The original graph of f. (b) The horizontal compression of in part (a) by a factor of 2, followed by a
reflection across the y-axis. (c) The vertical compression of in part (a) by a factor of 2, followed by a reflection across
the x-axis (Example 5).
y = ƒsxd
y = ƒsxd
x
y
(a) circle
–r
–r
r
r
0
x2
y2
r2
x
y
(b) ellipse, 0 c 1
–r
0
c2
x2
y2
r2
r
c
– r
c
x
y
(c) ellipse, c 1
–r
r
0
c2
x2
y2
r2
r
c
– r
c
r
FIGURE 1.36 Horizontal stretching or compression of a circle produces graphs of ellipses.

If the graph of Equation (1) horizontally stretches the circle; if the cir-
cle is compressed horizontally. In either case, the graph of Equation (1) is an ellipse
(Figure 1.36). Notice in Figure 1.36 that the y-intercepts of all three graphs are always
and r. In Figure 1.36b, the line segment joining the points is called the major
axis of the ellipse; the minor axis is the line segment joining The axes of the el-
lipse are reversed in Figure 1.36c: The major axis is the line segment joining the points
, and the minor axis is the line segment joining the points In both cases,
the major axis is the longer line segment.
If we divide both sides of Equation (1) by we obtain
(2)
where and If the major axis is horizontal; if the major axis
is vertical. The center of the ellipse given by Equation (2) is the origin (Figure 1.37).
Substituting for x, and for y, in Equation (2) results in
(3)
Equation (3) is the standard equation of an ellipse with center at (h, k). The geometric
definition and properties of ellipses are reviewed in Section 11.6.
sx - hd2
a2
+
s y - kd2
b2
= 1.
y - k
x - h
a 6 b,
a 7 b,
b = r.
a = rc
x2
a2
+
y2
b2
= 1
r2
,
s;rc, 0d.
s0, ;rd
s0, ;rd.
s;rc, 0d
-r
c 7 1
0 6 c 6 1,
x
y
–a
–b
b
a
Major axis
Center
FIGURE 1.37 Graph of the ellipse
where the major
axis is horizontal.
x2
a2
+
y2
b2
= 1, a 7 b,
Exercises 1.2
Algebraic Combinations
In Exercises 1 and 2, find the domains and ranges of and
1.
2.
In Exercises 3 and 4, find the domains and ranges of ƒ, g, , and
3.
4.
Composites of Functions
5. If and find the following.
a. b.
c. d.
e. f.
g. h.
6. If and find the following.
a. b.
c. d.
e. f.
g. h.
In Exercises 7–10, write a formula for
7.
8. hsxd = x2
gsxd = 2x - 1,
ƒ(x) = 3x + 4,
hsxd = 4 - x
gsxd = 3x,
ƒ(x) = x + 1,
ƒ g h.
g(g(x))
ƒ(ƒ(x))
g(g(2))
ƒ(ƒ(2))
g(ƒ(x))
ƒ(g(x))
g(ƒ(12))
ƒ(g(12))
gsxd = 1sx + 1d,
ƒsxd = x - 1
g(g(x))
ƒ(ƒ(x))
g(g(2))
ƒ(ƒ(-5))
g(ƒ(x))
ƒ(g(x))
g(ƒ(0))
ƒ(g(0))
gsxd = x2
- 3,
ƒsxd = x + 5
ƒsxd = 1, gsxd = 1 + 2x
ƒsxd = 2, gsxd = x2
+ 1
gƒ.
ƒg
ƒsxd = 2x + 1, gsxd = 2x - 1
ƒsxd = x, gsxd = 2x - 1
ƒ # g.
ƒ, g, ƒ + g,
9.
10.
Let and Ex-
press each of the functions in Exercises 11 and 12 as a composite in-
volving one or more of ƒ, g, h, and j.
11. a. b.
c. d.
e. f.
12. a. b.
c. d.
e. f.
13. Copy and complete the following table.
g(x) ƒ(x) (ƒ g)(x)
a. ?
b. 3x ?
c. ?
d. ?
e. ? x
f. ? x
1
x
1 +
1
x
x
x - 1
x
x - 1
2x2
- 5
2x - 5
x + 2
2x
x - 7

y = 2x3
- 3
y = 22x - 3
y = x - 6
y = x9
y = x32
y = 2x - 3
y = s2x - 6d3
y = 2sx - 3d3
y = 4x
y = x14
y = 22x
y = 2x - 3
jsxd = 2x.
ƒsxd = x - 3, gsxd = 2x, hsxd = x3
,
hsxd = 22 - x
gsxd =
x2
x2
+ 1
,
ƒsxd =
x + 2
3 - x
,
hsxd =
1
x
gsxd =
1
x + 4
,
ƒsxd = 2x + 1,

14. Copy and complete the following table.
g(x) ƒ(x) (ƒ g)(x)
a. ?
b. ?
c. ?
d. ?
15. Evaluate each expression using the given table of values
ƒ x ƒ
2x
ƒ x ƒ
2x
x
x + 1
x - 1
x
ƒ x ƒ
1
x - 1

22. The accompanying figure shows the graph of shifted to
two new positions. Write equations for the new graphs.
23. Match the equations listed in parts (a)–(d) to the graphs in the ac-
companying figure.
a. b.
c. d.
four new positions. Write an equation for each new graph.
x
y
(–2, 3)
(–4, –1)
(1, 4)
(2, 0)
(b)
(c) (d)
(a)
y = -x2
x
y
Position 2 Position 1
Position 4
Position 3
–4 –3 –2 –1 0 1 2 3
(–2, 2) (2, 2)
(–3, –2)
(1, –4)
1
2
3
y = sx + 3d2
- 2
y = sx + 2d2
+ 2
y = sx - 2d2
+ 2
y = sx - 1d2
- 4
x
y
Position (a)
Position (b)
y x2
–5
0
3
y = x2
x 0 1 2
ƒ(x) 1 0 1 2
g(x) 2 1 0 0
-1
-2
-1
-2
a. b. c.
d. e. f.
16. Evaluate each expression using the functions
a. b. c.
d. e. f.
In Exercises 17 and 18, (a) write formulas for and and
find the (b) domain and (c) range of each.
17.
18.
19. Let Find a function so that
20. Let Find a function so that
Shifting Graphs
two new positions. Write equations for the new graphs.
x
y
–7 0 4
Position (a) Position (b)
y –x2
y = -x2
(ƒ g)(x) = x + 2.
y = g(x)
ƒ(x) = 2x3
- 4.
(ƒ g)(x) = x.
y = g(x)
ƒ(x) =
x
x - 2
.
ƒ(x) = x2
, g(x) = 1 - 2x
ƒ(x) = 2x + 1, g(x) =
1
x
g ƒ
ƒ g
ƒsgs12dd
gsƒs0dd
ƒsƒs2dd
gsgs -1dd
gsƒs3dd
ƒsgs0dd
ƒ(x) = 2 - x, g(x) = b
-x, -2 … x 6 0
x - 1, 0 … x … 2.
ƒsgs1dd
gsƒs-2dd
gsgs2dd
ƒsƒs-1dd
gsƒs0dd
ƒsgs -1dd

Exercises 25–34 tell how many units and in what directions the graphs
of the given equations are to be shifted. Give an equation for the
shifted graph. Then sketch the original and shifted graphs together,
labeling each graph with its equation.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
Graph the functions in Exercises 35–54.
35. 36.
37. 38.
39. 40.
41. 42.
43. 44.
45. 46.
47. 48.
49. 50.
51. 52.
53. 54.
55. The accompanying figure shows the graph of a function ƒ(x) with
domain [0, 2] and range [0, 1]. Find the domains and ranges of the
following functions, and sketch their graphs.
a. b.
c. d.
e. f.
g. h. -ƒsx + 1d + 1
ƒs -xd
ƒsx - 1d
ƒsx + 2d
-ƒsxd
2ƒ(x)
ƒsxd - 1
ƒsxd + 2
x
y
0 2
1 y f(x)
y =
1
sx + 1d2
y =
1
x2
+ 1
y =
1
x2
- 1
y =
1
sx - 1d2
y =
1
x + 2
y =
1
x + 2
y =
1
x - 2
y =
1
x - 2
y = sx + 2d32
+ 1
y = 2
3
x - 1 - 1
y + 4 = x23
y = 1 - x23
y = sx - 8d23
y = sx + 1d23
y = 1 - 2x
y = 1 + 2x - 1
y = ƒ 1 - x ƒ - 1
y = ƒ x - 2 ƒ
y = 29 - x
y = 2x + 4
y = 1x2
Left 2, down 1
y = 1x Up 1, right 1
y =
1
2
sx + 1d + 5 Down 5, right 1
y = 2x - 7 Up 7
y = - 2x Right 3
y = 2x Left 0.81
y = x23
Right 1, down 1
y = x3
Left 1, down 1
x2
+ y2
= 25 Up 3, left 4
x2
+ y2
= 49 Down 3, left 2
56. The accompanying figure shows the graph of a function g(t) with
domain and range Find the domains and ranges
of the following functions, and sketch their graphs.
a. b.
c. d.
e. f.
g. h.
Vertical and Horizontal Scaling
Exercises 57–66 tell by what factor and direction the graphs of the
given functions are to be stretched or compressed. Give an equation
for the stretched or compressed graph.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
Graphing
In Exercises 67–74, graph each function, not by plotting points, but by
starting with the graph of one of the standard functions presented in
Figures 1.14–1.17 and applying an appropriate transformation.
67. 68.
69. 70.
71. 72.
73. 74.
Ellipses
Exercises 77–82 give equations of ellipses. Put each equation in stan-
dard form and sketch the ellipse.
77. 78.
79. 80. sx + 1d2
+ 2y2
= 4
3x2
+ s y - 2d2
= 3
16x2
+ 7y2
= 112
9x2
+ 25y2
= 225
y = 2ƒ x ƒ .
y = ƒ x2
- 1 ƒ .
y = s -2xd23
y = - 2
3
x
y =
2
x2
+ 1
y =
1
2x
- 1
y = s1 - xd3
+ 2
y = sx - 1d3
+ 2
y =
A
1 -
x
2
y = - 22x + 1
y = 1 - x3
, stretched horizontally by a factor of 2
y = 1 - x3
, compressed horizontally by a factor of 3
y = 24 - x2
, compressed vertically by a factor of 3
y = 24 - x2
y = 2x + 1, stretched vertically by a factor of 3
y = 2x + 1, compressed horizontally by a factor of 4
y = 1 +
1
x2
y = 1 +
1
x2
, compressed vertically by a factor of 2
y = x2
- 1, compressed horizontally by a factor of 2
y = x2
- 1, stretched vertically by a factor of 3
-gst - 4d
gs1 - td
gst - 2d
gs-t + 2d
1 - gstd
gstd + 3
-gstd
gs-td
t
y
–3
–2 0
–4
y g(t)
[-3, 0].
[-4, 0]

81.
82.
83. Write an equation for the ellipse shifted
4 units to the left and 3 units up. Sketch the ellipse and identify its
center and major axis.
84. Write an equation for the ellipse shifted
3 units to the right and 2 units down. Sketch the ellipse and iden-
tify its center and major axis.
Combining Functions
85. Assume that ƒ is an even function, g is an odd function, and both
ƒ and g are defined on the entire real line Which of the follow-
ing (where defined) are even? odd?
.
sx2
4d + sy2
25d = 1
sx2
16d + sy2
9d = 1
6 ax +
3
2
b
2
+ 9 ay -
1
2
b
2
= 54
3sx - 1d2
+ 2s y + 2d2
= 6 a. b. c.
d. e. f.
g. h. i.
86. Can a function be both even and odd? Give reasons for your
answer.
87. (Continuation of Example 1.) Graph the functions
and together with their (a) sum, (b) product,
(c) two differences, (d) two quotients.
88. Let and Graph ƒ and g together with
and g ƒ.
ƒ g
gsxd = x2
.
ƒsxd = x - 7
gsxd = 21 - x
ƒsxd = 2x
g g
ƒ ƒ
g ƒ
ƒ g
g2
= gg
ƒ2
= ƒƒ
gƒ
ƒg
ƒg
T
T
1.3
Trigonometric Functions
This section reviews radian measure and the basic trigonometric functions.
Angles
Angles are measured in degrees or radians. The number of radians in the central angle
within a circle of radius r is defined as the number of “radius units” contained in
the arc s subtended by that central angle. If we denote this central angle by when meas-
ured in radians, this means that (Figure 1.38), or
u = sr
u
A¿CB¿
(1)
s = ru (u in radians).
If the circle is a unit circle having radius , then from Figure 1.38 and Equation (1),
we see that the central angle measured in radians is just the length of the arc that the an-
gle cuts from the unit circle. Since one complete revolution of the unit circle is 360 or
radians, we have
(2)
and
Table 1.2 shows the equivalence between degree and radian measures for some basic
angles.
1 radian =
180
p (L 57.3) degrees or 1 degree =
p
180
(L 0.017) radians.
p radians = 180°
2p
°
u
r = 1
B'
B
s
A'
C A
r
1
θ
Circle of radius r
Unit circl
e
FIGURE 1.38 The radian measure of the
central angle is the number
For a unit circle of radius is the
length of arc AB that central angle ACB
cuts from the unit circle.
r = 1, u
u = sr.
A¿CB¿
TABLE 1.2 Angles measured in degrees and radians
Degrees 0 30 45 60 90 120 135 150 180 270 360
(radians) 0 2p
3p
2
p
5p
6
3p
4
2p
3
p
2
p
3
p
4
p
6
p
4
p
2
3p
4
p
U
45
90
135
180

x
y
x
y
Positive
measure
Initial ray
Terminal ray
Terminal
ray
Initial ray
Negative
measure
FIGURE 1.39 Angles in standard position in the xy-plane.
x
y
4
9
x
y
3
x
y
4
–3
x
y
2
–5
FIGURE 1.40 Nonzero radian measures can be positive or negative and can go beyond 2p.
hypotenuse
adjacent
opposite

sin

opp
hyp

adj
hyp
cos
tan

opp
adj
csc

hyp
opp

hyp
adj
sec
cot

adj
opp
FIGURE 1.41 Trigonometric
ratios of an acute angle.
An angle in the xy-plane is said to be in standard position if its vertex lies at the origin
and its initial ray lies along the positive x-axis (Figure 1.39). Angles measured counter-
clockwise from the positive x-axis are assigned positive measures; angles measured clock-
wise are assigned negative measures.
Angles describing counterclockwise rotations can go arbitrarily far beyond radi-
ans or 360 . Similarly, angles describing clockwise rotations can have negative measures
of all sizes (Figure 1.40).
°
2p
Angle Convention: Use Radians From now on, in this book it is assumed that all angles
are measured in radians unless degrees or some other unit is stated explicitly. When we talk
about the angle , we mean radians (which is 60 ), not degrees. We use radians
because it simplifies many of the operations in calculus, and some results we will obtain
involving the trigonometric functions are not true when angles are measured in degrees.
The Six Basic Trigonometric Functions
You are probably familiar with defining the trigonometric functions of an acute angle in
terms of the sides of a right triangle (Figure 1.41). We extend this definition to obtuse and
negative angles by first placing the angle in standard position in a circle of radius r.
We then define the trigonometric functions in terms of the coordinates of the point P(x, y)
where the angle’s terminal ray intersects the circle (Figure 1.42).
sine: cosecant:
cosine: secant:
tangent: cotangent:
These extended definitions agree with the right-triangle definitions when the angle is acute.
Notice also that whenever the quotients are defined,
csc u =
1
sin u
sec u =
1
cos u
cot u =
1
tan u
tan u =
sin u
cos u
cot u =
x
y
tan u =
y
x
sec u =
r
x
cos u =
x
r
csc u =
r
y
sin u =
y
r
p3
°
p3
p3
x
y
P(x, y)
r
r
O

y
x
FIGURE 1.42 The trigonometric
functions of a general angle are
defined in terms of x, y, and r.
u

As you can see, and are not defined if This means they are not
defined if is Similarly, and are not defined for values of
for which namely
The exact values of these trigonometric ratios for some angles can be read from the
triangles in Figure 1.43. For instance,
The CAST rule (Figure 1.44) is useful for remembering when the basic trigonometric func-
tions are positive or negative. For instance, from the triangle in Figure 1.45, we see that
sin
2p
3
=
23
2
, cos
2p
3
= -
1
2
, tan
2p
3
= - 23.
tan
p
3
= 23
tan
p
6
=
1
23
tan
p
4
= 1
cos
p
3
=
1
2
cos
p
6
=
23
2
cos
p
4
=
1
22
sin
p
3
=
23
2
sin
p
6
=
1
2
sin
p
4
=
1
22
u = 0, ;p, ;2p, Á .
y = 0,
u
csc u
cot u
;p2, ;3p2, Á .
u
x = cos u = 0.
sec u
tan u
1
1

2

4

4
2
FIGURE 1.43 Radian angles and side
lengths of two common triangles.
1

3

2

6
2 3
y
x
S
sin pos
A
all pos
T
tan pos
C
cos pos
x
y
3
2
1
2
1
2
3

⎛
⎝
⎛
⎝
⎛
⎝
⎛
⎝
2
3
, ,
cos 2
3
sin
1
2
–
2
P
3
FIGURE 1.44 The CAST rule,
remembered by the statement
“Calculus Activates Student
Thinking,” tells which
trigonometric functions are
positive in each quadrant.
FIGURE 1.45 The triangle for
calculating the sine and cosine of
radians. The side lengths come from the
geometry of right triangles.
2p3
Using a similar method we determined the values of sin , cos , and tan shown in Table 1.3.
u
u
u
TABLE 1.3 Values of and for selected values of
Degrees 0 30 45 60 90 120 135 150 180 270 360
(radians) 0
0 0 1 0 0
0 1 0 0 1
0 1 0 1 0 0
- 23
3
-1
- 23
23
23
3
-1
tan u
-1
- 23
2
- 22
2
-
1
2
1
2
22
2
23
2
22
2
- 22
2
-1
cos u
-1
1
2
22
2
23
2
23
2
22
2
1
2
- 22
2
-1
- 22
2
sin u
2p
3p
2
p
5p
6
3p
4
2p
3
p
2
p
3
p
4
p
6
p
4
p
2
3p
4
p
u
45
90
135
180
u
tan u
sin u, cos u,

Periodicity and Graphs of the Trigonometric Functions
When an angle of measure and an angle of measure are in standard position, their
terminal rays coincide. The two angles therefore have the same trigonometric function values:
, and so on. Similarly,
, and so on. We describe this repeating behavior by saying that the six
basic trigonometric functions are periodic.
sin(u - 2p) = sin u
cos(u - 2p) = cos u,
tan(u + 2p) = tan u
sin(u + 2p) = sin u,
u + 2p
u
DEFINITION A function ƒ(x) is periodic if there is a positive number p such that
for every value of x. The smallest such value of p is the period of ƒ.
ƒ(x + p) = ƒ(x)
When we graph trigonometric functions in the coordinate plane, we usually denote the in-
dependent variable by x instead of Figure 1.46 shows that the tangent and cotangent
functions have period , and the other four functions have period Also, the sym-
metries in these graphs reveal that the cosine and secant functions are even and the other
four functions are odd (although this does not prove those results).
2p.
p = p
u.
ysinx
(a) (b) (c)
(f)
(e)
(d)
x
x
x
y
x
y y
x
y
x
y y
y cos x
Domain: – x
Range: –1 y 1
Period: 2
0
– 2
–
2

2
3
2
0
– 2
–
2

2
3
2
y sin x
y tan x
Domain: – x
Range: –1 y 1
Period: 2
3
2
– – –
2
0
2
3
2

2
3
2
Domain: x , , . . .
Range: – y
Period:
y sec x y csc x y cot x
3
2
– – –
2
0
1

2
3
2
0
1
– 2
–
2

2
3
2
0
1
– 2
–
2

2
3
2
Domain: x 0, , 2, . . .
Range: y –1 or y 1
Period: 2
Domain: x 0, , 2, . . .
Range: – y
Period:
Domain: x , , . . .
Range: y –1 or y 1
Period: 2

2
3
2
FIGURE 1.46 Graphs of the six basic trigonometric functions using radian measure. The shading
for each trigonometric function indicates its periodicity.
Even
secs-xd = sec x
coss-xd = cos x
Odd
cots-xd = -cot x
cscs-xd = -csc x
tans-xd = -tan x
sins-xd = -sin x
Periods of Trigonometric Functions
Period
Period
cscsx + 2pd = csc x
secsx + 2pd = sec x
cossx + 2pd = cos x
sinsx + 2pd = sin x
2P :
cotsx + pd = cot x
tansx + pd = tan x
P :
Trigonometric Identities
The coordinates of any point P(x, y) in the plane can be expressed in terms of the point’s
distance r from the origin and the angle that ray OP makes with the positive x-axis
(Figure 1.42). Since and we have
When we can apply the Pythagorean theorem to the reference right triangle in
Figure 1.47 and obtain the equation
r = 1
x = r cos u, y = r sin u.
yr = sin u,
xr = cos u
u
(3)
cos2
u + sin2
u = 1.
y
x

1
P(cos , sin )
x2
y2
1
cos
sin
O
FIGURE 1.47 The reference
triangle for a general angle u.

This equation, true for all values of , is the most frequently used identity in trigonometry.
Dividing this identity in turn by and gives
sin2
u
cos2
u
u
1 + cot2
u = csc2
u
1 + tan2
u = sec2
u
The following formulas hold for all angles A and B (Exercise 58).
Addition Formulas
(4)
sinsA + Bd = sin A cos B + cos A sin B
cossA + Bd = cos A cos B - sin A sin B
There are similar formulas for and (Exercises 35 and 36). All
the trigonometric identities needed in this book derive from Equations (3) and (4). For ex-
ample, substituting for both A and B in the addition formulas gives
u
sin sA - Bd
cos sA - Bd
Double-Angle Formulas
(5)
sin 2u = 2 sin u cos u
cos 2u = cos2
u - sin2
u
Additional formulas come from combining the equations
We add the two equations to get and subtract the second from the
first to get This results in the following identities, which are useful
in integral calculus.
2 sin2
u = 1 - cos 2u.
2 cos2
u = 1 + cos 2u
cos2
u + sin2
u = 1, cos2
u - sin2
u = cos 2u.
The Law of Cosines
If a, b, and c are sides of a triangle ABC and if is the angle opposite c, then
u
Half-Angle Formulas
(6)
(7)
sin2
u =
1 - cos 2u
2
cos2
u =
1 + cos 2u
2
(8)
c2
= a2
+ b2
- 2ab cos u.
This equation is called the law of cosines.

We can see why the law holds if we introduce coordinate axes with the origin at C and
the positive x-axis along one side of the triangle, as in Figure 1.48. The coordinates of A
are (b, 0); the coordinates of B are The square of the distance between A
and B is therefore
The law of cosines generalizes the Pythagorean theorem. If then
and
Transformations of Trigonometric Graphs
The rules for shifting, stretching, compressing, and reflecting the graph of a function sum-
marized in the following diagram apply to the trigonometric functions we have discussed
in this section.
c2
= a2
+ b2
.
cos u = 0
u = p2,
= a2
+ b2
- 2ab cos u.
= a2
scos2
u + sin2
ud + b2
- 2ab cos u
('')''*
1
c2
= sa cos u - bd2
+ sa sin ud2
sa cos u, a sin ud.
y
x
C
a
c
b
B(a cos , a sin )
A(b, 0)

FIGURE 1.48 The square of the distance
between A and B gives the law of cosines.
y = aƒ(bsx + cdd + d
Vertical stretch or compression;
reflection about x-axis if negative
Vertical shift
Horizontal stretch or compression;
reflection about y-axis if negative
Horizontal shift
The transformation rules applied to the sine function give the general sine function
or sinusoid formula
where is the amplitude, is the period, C is the horizontal shift, and D is the
vertical shift. A graphical interpretation of the various terms is revealing and given below.
ƒ B ƒ
ƒ A ƒ
ƒ(x) = A sin a
2p
B
(x - C)b + D,
D
y
x
Vertical
shift (D)
Horizontal
shift (C)
D A
D A
Amplitude (A)
This distance is
the period (B).
This axis is the
line y D.
y A sin D
(x C)
( )
2
B
0
Two Special Inequalities
For any angle measured in radians,
u
- ƒ u ƒ … sin u … ƒ u ƒ and - ƒ u ƒ … 1 - cos u … ƒ u ƒ .

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