E All the mathematical tools an economist needs s Essential Mathematics s are provided in this worldwide bestseller. e for n t i Now fully updated, with new problems added for each chapter. a Economic Analysis l M a New! Learning online with MyMathLab Global t h ‘Allows students to work at their own pace, get immediate feedback, and overcome e m problems by using the step-wise advice. This is an excellent tool for all students.’ FOURTH EDITION a Jana Vyrastekova, University of Nijmegen, the Netherlands t i c s f o r E c o Go to www.mymathlab.com/global – your gateway to all the online resources n for this book. o m • MyMathLab Global provides you with the opportunity for unlimited practice, i guided solutions with tips and hints to help you solve challenging questions, c an interactive eBook, as well as a personalised study plan to help focus your A revision efforts on the topics where you need most support. n a • Short answers are available to almost all of the 1,000 problems in the book l y for students to self check. In addition, a Students’ Manual is provided in the s online resources, with extended worked answers to selected problems. i s • If you have purchased this text as part of a pack, the book contains a code and full instructions allowing you to register for access to MyMathLab Global. If you have purchased this text on its own, you can still purchase access online FOURTH at www.mymathlab.com/global. See the Guided Tour at the front of this EDITION text for more details. wHS Knut Sydsæter is an Emeritus Professor of Mathematics in the Economics Department itayd hm at the University of Oslo, where he has been teaching mathematics for economists s Smæ since 1965. t t roe Ø Peter Hammond is currently a Professor of Economics at the University of Warwick, mnr d& where he moved in 2007 after becoming an Emeritus Professor at Stanford University. He has taught mathematics for economists at both universities. Knut Sydsæter & Peter Hammond Arne Strøm has extensive experience in teaching mathematics for economists in the Department of Economics at the University of Oslo. with Arne StrØm www.pearson-books.com ESSENTIAL MATHEMATICS FOR EC ONOMIC A N A LYSIS ESSENTIAL MATHEMATICS FOR E C O N O M I C A N A LY S I S FOURTH EDITION Knut Sydsæter and Peter Hammond with Arne Strøm Pearson Education Limited Edinburgh Gate Harlow Essex CM20 2JE England and Associated Companies throughout the world Visit us on the World Wide Web at: www.pearson.com/uk First published by Prentice-Hall, Inc. 1995 Second edition published 2006 Third edition published 2008 Fourth edition published by Pearson Education Limited 2012 TothememoryofmyparentsElsie(1916–2007)and © Prentice-Hall, Inc. 1995 © Knut Sydsæter and Peter Hammond 2002, 2006, 2008, 2012 Fred(1916–2008),myfirstteachersofMathematics, The rights of Knut Sydsæter and Peter Hammond to be identified as authors of this work basic Economics, and many more important things. have been asserted by them in accordance with the Copyright, Designs and Patents Act 1988. 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 — Peter or otherwise, without either the prior written permission of the publisher or a licence permitting restricted copying in the United Kingdom issued by the Copyright Licensing Agency Ltd, Saffron House, 6−10 Kirby Street, London EC1N 8TS. Pearson Education is not responsible for the content of third-party internet sites. ISBN 978-0-273-76068-9 British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library 10 9 8 7 6 5 4 3 2 1 16 15 14 13 12 Typeset in 10/13 pt Times Roman by Matematisk Sats and Arne Strøm, Norway Printed and bound by Ashford Colour Press Ltd, Gosport, UK EssentialMath.forEcon.Analysis,4thedn EME4_A0100.TEX,17April2012,19:33 Pagev TothememoryofmyparentsElsie(1916–2007)and Fred(1916–2008),myfirstteachersofMathematics, basic Economics, and many more important things. — Peter EssentialMath.forEcon.Analysis,4thedn EME4_A0100.TEX,17April2012,19:33 Pagev C O N T E N T S Preface xi 3.3 DoubleSums 59 3.4 AFewAspectsofLogic 61 1 Introductory Topics I: Algebra 1 3.5 MathematicalProofs 67 3.6 EssentialsofSetTheory 69 1.1 TheRealNumbers 1 3.7 MathematicalInduction 75 1.2 IntegerPowers 4 ReviewProblemsforChapter3 77 1.3 RulesofAlgebra 10 1.4 Fractions 14 4 Functions of One Variable 79 1.5 FractionalPowers 19 1.6 Inequalities 24 4.1 Introduction 79 1.7 IntervalsandAbsoluteValues 29 4.2 BasicDefinitions 80 ReviewProblemsforChapter1 32 4.3 GraphsofFunctions 86 4.4 LinearFunctions 89 2 Introductory Topics II: 4.5 LinearModels 95 Equations 35 4.6 QuadraticFunctions 99 2.1 HowtoSolveSimpleEquations 35 4.7 Polynomials 105 2.2 EquationswithParameters 38 4.8 PowerFunctions 112 2.3 QuadraticEquations 41 4.9 ExponentialFunctions 114 2.4 LinearEquationsinTwoUnknowns 46 4.10 LogarithmicFunctions 119 2.5 NonlinearEquations 48 ReviewProblemsforChapter4 124 ReviewProblemsforChapter2 49 5 Properties of Functions 127 3 Introductory Topics III: 5.1 ShiftingGraphs 127 Miscellaneous 51 5.2 NewFunctionsfromOld 132 3.1 SummationNotation 51 5.3 InverseFunctions 136 3.2 RulesforSums. Newton’sBinomial 5.4 GraphsofEquations 143 Formula 55 5.5 DistanceinthePlane. Circles 146 EssentialMath.forEcon.Analysis,4thedn EME4_A0207.TEX,24April2012,22:12 Pagevii C O N T E N T S Preface xi 3.3 DoubleSums 59 3.4 AFewAspectsofLogic 61 1 Introductory Topics I: Algebra 1 3.5 MathematicalProofs 67 3.6 EssentialsofSetTheory 69 1.1 TheRealNumbers 1 3.7 MathematicalInduction 75 1.2 IntegerPowers 4 ReviewProblemsforChapter3 77 1.3 RulesofAlgebra 10 1.4 Fractions 14 4 Functions of One Variable 79 1.5 FractionalPowers 19 1.6 Inequalities 24 4.1 Introduction 79 1.7 IntervalsandAbsoluteValues 29 4.2 BasicDefinitions 80 ReviewProblemsforChapter1 32 4.3 GraphsofFunctions 86 4.4 LinearFunctions 89 2 Introductory Topics II: 4.5 LinearModels 95 Equations 35 4.6 QuadraticFunctions 99 2.1 HowtoSolveSimpleEquations 35 4.7 Polynomials 105 2.2 EquationswithParameters 38 4.8 PowerFunctions 112 2.3 QuadraticEquations 41 4.9 ExponentialFunctions 114 2.4 LinearEquationsinTwoUnknowns 46 4.10 LogarithmicFunctions 119 2.5 NonlinearEquations 48 ReviewProblemsforChapter4 124 ReviewProblemsforChapter2 49 5 Properties of Functions 127 3 Introductory Topics III: 5.1 ShiftingGraphs 127 Miscellaneous 51 5.2 NewFunctionsfromOld 132 3.1 SummationNotation 51 5.3 InverseFunctions 136 3.2 RulesforSums. Newton’sBinomial 5.4 GraphsofEquations 143 Formula 55 5.5 DistanceinthePlane. Circles 146 EssentialMath.forEcon.Analysis,4thedn EME4_A0207.TEX,24April2012,22:12 Pagevii vviiiiii CCOONNTETNENTSTS CONTENTS ix 5.6 GeneralFunctions 150 9 Integration 293 12.5 ElasticityofSubstitution 428 15.5 TheTranspose 562 ReviewProblemsforChapter5 153 9.1 IndefiniteIntegrals 293 12.6 HomogeneousFunctionsof 15.6 GaussianElimination 565 TwoVariables 431 15.7 Vectors 570 9.2 AreaandDefiniteIntegrals 299 6 Differentiation 155 12.7 HomogeneousandHomothetic 15.8 GeometricInterpretationofVectors 573 9.3 PropertiesofDefiniteIntegrals 305 Functions 435 15.9 LinesandPlanes 578 6.1 SlopesofCurves 155 9.4 EconomicApplications 309 12.8 LinearApproximations 440 ReviewProblemsforChapter15 582 6.2 TangentsandDerivatives 157 9.5 IntegrationbyParts 315 9.6 IntegrationbySubstitution 319 12.9 Differentials 444 6.3 IncreasingandDecreasingFunctions 163 9.7 InfiniteIntervalsofIntegration 324 12.10 SystemsofEquations 449 16 Determinants and 6.4 RatesofChange 165 9.8 AGlimpseatDifferentialEquations 330 12.11 DifferentiatingSystemsofEquations 452 Inverse Matrices 585 6.5 ADashofLimits 169 9.9 SeparableandLinearDifferential ReviewProblemsforChapter12 458 16.1 DeterminantsofOrder2 585 6.6 SimpleRulesforDifferentiation 174 Equations 336 16.2 DeterminantsofOrder3 589 6.7 Sums,Products,andQuotients 178 13 Multivariable ReviewProblemsforChapter9 341 16.3 DeterminantsofOrdern 593 6.8 ChainRule 184 Optimization 461 16.4 BasicRulesforDeterminants 596 6.9 Higher-OrderDerivatives 188 10 Topics in Financial 13.1 TwoVariables: NecessaryConditions 461 16.5 ExpansionbyCofactors 601 6.10 ExponentialFunctions 194 Economics 345 13.2 TwoVariables: SufficientConditions 466 16.6 TheInverseofaMatrix 604 6.11 LogarithmicFunctions 197 ReviewProblemsforChapter6 203 10.1 InterestPeriodsandEffectiveRates 345 13.3 LocalExtremePoints 470 16.7 AGeneralFormulafortheInverse 610 10.2 ContinuousCompounding 349 13.4 LinearModelswithQuadratic 16.8 Cramer’sRule 613 7 Derivatives in Use 205 10.3 PresentValue 351 Objectives 475 16.9 TheLeontiefModel 616 10.4 GeometricSeries 353 13.5 TheExtremeValueTheorem 482 ReviewProblemsforChapter16 621 7.1 ImplicitDifferentiation 205 10.5 TotalPresentValue 359 13.6 ThreeorMoreVariables 487 7.2 EconomicExamples 210 10.6 MortgageRepayments 364 13.7 ComparativeStaticsandthe 17 Linear Programming 623 7.3 DifferentiatingtheInverse 214 10.7 InternalRateofReturn 369 EnvelopeTheorem 491 17.1 AGraphicalApproach 623 7.4 LinearApproximations 217 10.8 AGlimpseatDifferenceEquations 371 ReviewProblemsforChapter13 495 17.2 IntroductiontoDualityTheory 629 7.5 PolynomialApproximations 221 ReviewProblemsforChapter10 374 17.3 TheDualityTheorem 633 7.6 Taylor’sFormula 225 14 Constrained Optimization 497 17.4 AGeneralEconomicInterpretation 636 7.7 WhyEconomistsUseElasticities 228 11 Functions of Many 14.1 TheLagrangeMultiplierMethod 497 17.5 ComplementarySlackness 638 7.8 Continuity 233 Variables 377 14.2 InterpretingtheLagrangeMultiplier 504 ReviewProblemsforChapter17 643 7.9 MoreonLimits 237 11.1 FunctionsofTwoVariables 377 14.3 SeveralSolutionCandidates 507 7.10 IntermediateValueTheorem. Appendix: Geometry 645 11.2 PartialDerivativeswithTwoVariables 381 14.4 WhytheLagrangeMethodWorks 509 Newton’sMethod 245 11.3 GeometricRepresentation 387 14.5 SufficientConditions 513 The Greek Alphabet 647 7.11 InfiniteSequences 249 11.4 SurfacesandDistance 393 14.6 AdditionalVariablesandConstraints 516 7.12 L’Hôpital’sRule 251 11.5 FunctionsofMoreVariables 396 14.7 ComparativeStatics 522 Answers to the Problems 649 ReviewProblemsforChapter7 256 11.6 PartialDerivativeswithMoreVariables 400 14.8 NonlinearProgramming: 11.7 EconomicApplications 404 ASimpleCase 526 Index 739 8 Single-Variable 11.8 PartialElasticities 406 14.9 MultipleInequalityConstraints 532 Optimization 259 ReviewProblemsforChapter11 408 14.10 NonnegativityConstraints 537 8.1 Introduction 259 ReviewProblemsforChapter14 541 12 Tools for Comparative 8.2 SimpleTestsforExtremePoints 262 Statics 411 15 Matrix and Vector 8.3 EconomicExamples 266 Algebra 545 8.4 TheExtremeValueTheorem 270 12.1 ASimpleChainRule 411 8.5 FurtherEconomicExamples 276 12.2 ChainRulesforManyVariables 416 15.1 SystemsofLinearEquations 545 8.6 LocalExtremePoints 281 12.3 ImplicitDifferentiationalonga 15.2 MatricesandMatrixOperations 548 8.7 InflectionPoints 287 LevelCurve 420 15.3 MatrixMultiplication 551 ReviewProblemsforChapter8 291 12.4 MoreGeneralCases 424 15.4 RulesforMatrixMultiplication 556 EssentialMath.forEcon.Analysis,4thedn EME4_A0207.TEX,24April2012,22:12 Pageviii EssentialMath.forEcon.Analysis,4thedn EME4_A0207.TEX,24April2012,22:12 Pageix viii CONTENTS CCOONNTTEENNTTSS iixx 5.6 GeneralFunctions 150 9 Integration 293 12.5 ElasticityofSubstitution 428 15.5 TheTranspose 562 ReviewProblemsforChapter5 153 9.1 IndefiniteIntegrals 293 12.6 HomogeneousFunctionsof 15.6 GaussianElimination 565 TwoVariables 431 15.7 Vectors 570 9.2 AreaandDefiniteIntegrals 299 6 Differentiation 155 12.7 HomogeneousandHomothetic 15.8 GeometricInterpretationofVectors 573 9.3 PropertiesofDefiniteIntegrals 305 Functions 435 15.9 LinesandPlanes 578 6.1 SlopesofCurves 155 9.4 EconomicApplications 309 12.8 LinearApproximations 440 ReviewProblemsforChapter15 582 6.2 TangentsandDerivatives 157 9.5 IntegrationbyParts 315 9.6 IntegrationbySubstitution 319 12.9 Differentials 444 6.3 IncreasingandDecreasingFunctions 163 9.7 InfiniteIntervalsofIntegration 324 12.10 SystemsofEquations 449 16 Determinants and 6.4 RatesofChange 165 9.8 AGlimpseatDifferentialEquations 330 12.11 DifferentiatingSystemsofEquations 452 Inverse Matrices 585 6.5 ADashofLimits 169 9.9 SeparableandLinearDifferential ReviewProblemsforChapter12 458 16.1 DeterminantsofOrder2 585 6.6 SimpleRulesforDifferentiation 174 Equations 336 16.2 DeterminantsofOrder3 589 6.7 Sums,Products,andQuotients 178 13 Multivariable ReviewProblemsforChapter9 341 16.3 DeterminantsofOrdern 593 6.8 ChainRule 184 Optimization 461 16.4 BasicRulesforDeterminants 596 6.9 Higher-OrderDerivatives 188 10 Topics in Financial 13.1 TwoVariables: NecessaryConditions 461 16.5 ExpansionbyCofactors 601 6.10 ExponentialFunctions 194 Economics 345 13.2 TwoVariables: SufficientConditions 466 16.6 TheInverseofaMatrix 604 6.11 LogarithmicFunctions 197 ReviewProblemsforChapter6 203 10.1 InterestPeriodsandEffectiveRates 345 13.3 LocalExtremePoints 470 16.7 AGeneralFormulafortheInverse 610 10.2 ContinuousCompounding 349 13.4 LinearModelswithQuadratic 16.8 Cramer’sRule 613 7 Derivatives in Use 205 10.3 PresentValue 351 Objectives 475 16.9 TheLeontiefModel 616 10.4 GeometricSeries 353 13.5 TheExtremeValueTheorem 482 ReviewProblemsforChapter16 621 7.1 ImplicitDifferentiation 205 10.5 TotalPresentValue 359 13.6 ThreeorMoreVariables 487 7.2 EconomicExamples 210 10.6 MortgageRepayments 364 13.7 ComparativeStaticsandthe 17 Linear Programming 623 7.3 DifferentiatingtheInverse 214 10.7 InternalRateofReturn 369 EnvelopeTheorem 491 17.1 AGraphicalApproach 623 7.4 LinearApproximations 217 10.8 AGlimpseatDifferenceEquations 371 ReviewProblemsforChapter13 495 17.2 IntroductiontoDualityTheory 629 7.5 PolynomialApproximations 221 ReviewProblemsforChapter10 374 17.3 TheDualityTheorem 633 7.6 Taylor’sFormula 225 14 Constrained Optimization 497 17.4 AGeneralEconomicInterpretation 636 7.7 WhyEconomistsUseElasticities 228 11 Functions of Many 14.1 TheLagrangeMultiplierMethod 497 17.5 ComplementarySlackness 638 7.8 Continuity 233 Variables 377 14.2 InterpretingtheLagrangeMultiplier 504 ReviewProblemsforChapter17 643 7.9 MoreonLimits 237 11.1 FunctionsofTwoVariables 377 14.3 SeveralSolutionCandidates 507 7.10 IntermediateValueTheorem. Appendix: Geometry 645 11.2 PartialDerivativeswithTwoVariables 381 14.4 WhytheLagrangeMethodWorks 509 Newton’sMethod 245 11.3 GeometricRepresentation 387 14.5 SufficientConditions 513 The Greek Alphabet 647 7.11 InfiniteSequences 249 11.4 SurfacesandDistance 393 14.6 AdditionalVariablesandConstraints 516 7.12 L’Hôpital’sRule 251 11.5 FunctionsofMoreVariables 396 14.7 ComparativeStatics 522 Answers to the Problems 649 ReviewProblemsforChapter7 256 11.6 PartialDerivativeswithMoreVariables 400 14.8 NonlinearProgramming: 11.7 EconomicApplications 404 ASimpleCase 526 Index 739 8 Single-Variable 11.8 PartialElasticities 406 14.9 MultipleInequalityConstraints 532 Optimization 259 ReviewProblemsforChapter11 408 14.10 NonnegativityConstraints 537 8.1 Introduction 259 ReviewProblemsforChapter14 541 12 Tools for Comparative 8.2 SimpleTestsforExtremePoints 262 Statics 411 15 Matrix and Vector 8.3 EconomicExamples 266 Algebra 545 8.4 TheExtremeValueTheorem 270 12.1 ASimpleChainRule 411 8.5 FurtherEconomicExamples 276 12.2 ChainRulesforManyVariables 416 15.1 SystemsofLinearEquations 545 8.6 LocalExtremePoints 281 12.3 ImplicitDifferentiationalonga 15.2 MatricesandMatrixOperations 548 8.7 InflectionPoints 287 LevelCurve 420 15.3 MatrixMultiplication 551 ReviewProblemsforChapter8 291 12.4 MoreGeneralCases 424 15.4 RulesforMatrixMultiplication 556 EssentialMath.forEcon.Analysis,4thedn EME4_A0207.TEX,24April2012,22:12 Pageviii EssentialMath.forEcon.Analysis,4thedn EME4_A0207.TEX,24April2012,22:12 Pageix