Basic Mathematics for Economists Economicsstudentswillwelcometheneweditionofthisexcellenttextbook.Given thatmanystudentscomeintoeconomicscourseswithouthavingstudiedmathematics foranumberofyears,thisclearlywrittenbookwillhelptodevelopquantitativeskills ineventheleastnumeratestudentuptotherequiredlevelforageneralEconomics orBusinessStudiescourse.Allexplanationsofmathematicalconceptsaresetoutin thecontextofapplicationsineconomics. Thisneweditionincorporatesseveralnewfeatures,includingnewsectionson: • financialmathematics • continuousgrowth • matrixalgebra Improvedpedagogicalfeatures,suchaslearningobjectivesandendofchapterques- tions, along with an overall example-led format and the use of Microsoft Excel for relevantapplicationsmeanthatthistextbookwillcontinuetobeapopularchoicefor bothstudentsandtheirlecturers. MikeRosserisPrincipalLecturerinEconomicsintheBusinessSchoolatCoventry University. © 1993, 2003 Mike Rosser Basic Mathematics for Economists Second Edition Mike Rosser © 1993, 2003 Mike Rosser Firsteditionpublished1993 byRoutledge Thiseditionpublished2003 byRoutledge 11NewFetterLane,LondonEC4P4EE SimultaneouslypublishedintheUSAandCanada byRoutledge 29West35thStreet,NewYork,NY10001 RoutledgeisanimprintoftheTaylor&FrancisGroup This edition published in the Taylor & Francis e-Library, 2003. ©1993,2003MikeRosser Allrightsreserved.Nopartofthisbookmaybereprintedorreproducedor utilisedinanyformorbyanyelectronic,mechanical,orothermeans,now knownorhereafterinvented,includingphotocopyingandrecording,orinany informationstorageorretrievalsystem,withoutpermissioninwritingfrom thepublishers. BritishLibraryCataloguinginPublicationData AcataloguerecordforthisbookisavailablefromtheBritishLibrary LibraryofCongressCataloginginPublicationData Acatalogrecordforthisbookhasbeenrequested ISBN 0-203-42263-5 Master e-book ISBN ISBN 0-203-42439-5 (Adobe eReader Format) ISBN0–415–26783–8(hbk) ISBN0–415–26784–6(pbk) © 1993, 2003 Mike Rosser Contents Preface PrefacetoSecondEdition Acknowledgements 1 Introduction 1.1 Whystudymathematics? 1.2 Calculatorsandcomputers 1.3 Usingthebook 2 Arithmetic 2.1 Revisionofbasicconcepts 2.2 Multipleoperations 2.3 Brackets 2.4 Fractions 2.5 Elasticityofdemand 2.6 Decimals 2.7 Negativenumbers 2.8 Powers 2.9 Rootsandfractionalpowers 2.10 Logarithms 3 Introductiontoalgebra 3.1 Representation 3.2 Evaluation 3.3 Simplification:additionandsubtraction 3.4 Simplification:multiplication 3.5 Simplification:factorizing 3.6 Simplification:division 3.7 Solvingsimpleequations (cid:1) 3.8 Thesummationsign 3.9 Inequalitysigns © 1993, 2003 Mike Rosser 4 Graphsandfunctions 4.1 Functions 4.2 Inversefunctions 4.3 Graphsoflinearfunctions 4.4 Fittinglinearfunctions 4.5 Slope 4.6 Budgetconstraints 4.7 Non-linearfunctions 4.8 Compositefunctions 4.9 UsingExceltoplotfunctions 4.10 Functionswithtwoindependentvariables 4.11 Summingfunctionshorizontally 5 Linearequations 5.1 Simultaneouslinearequationsystems 5.2 Solvingsimultaneouslinearequations 5.3 Graphicalsolution 5.4 Equatingtosamevariable 5.5 Substitution 5.6 Rowoperations 5.7 Morethantwounknowns 5.8 Whichmethod? 5.9 Comparativestaticsandthereducedformof aneconomicmodel 5.10 Pricediscrimination 5.11 Multiplantmonopoly Appendix:linearprogramming 6 Quadraticequations 6.1 Solvingquadraticequations 6.2 Graphicalsolution 6.3 Factorization 6.4 Thequadraticformula 6.5 Quadraticsimultaneousequations 6.6 Polynomials 7 Financialmathematics:series,timeandinvestment 7.1 Discreteandcontinuousgrowth 7.2 Interest 7.3 Partyearinvestmentandtheannualequivalentrate 7.4 Timeperiods,initialamountsandinterestrates 7.5 Investmentappraisal:netpresentvalue 7.6 Theinternalrateofreturn 7.7 Geometricseriesandannuities © 1993, 2003 Mike Rosser 7.8 Perpetualannuities 7.9 Loanrepayments 7.10 Otherapplicationsofgrowthanddecline 8 Introductiontocalculus 8.1 Thedifferentialcalculus 8.2 Rulesfordifferentiation 8.3 Marginalrevenueandtotalrevenue 8.4 Marginalcostandtotalcost 8.5 Profitmaximization 8.6 Respecifyingfunctions 8.7 Pointelasticityofdemand 8.8 Taxyield 8.9 TheKeynesianmultiplier 9 Unconstrainedoptimization 9.1 First-orderconditionsforamaximum 9.2 Second-orderconditionforamaximum 9.3 Second-orderconditionforaminimum 9.4 Summaryofsecond-orderconditions 9.5 Profitmaximization 9.6 Inventorycontrol 9.7 Comparativestaticeffectsoftaxes 10 Partialdifferentiation 10.1 Partialdifferentiationandthemarginalproduct 10.2 Furtherapplicationsofpartialdifferentiation 10.3 Second-orderpartialderivatives 10.4 Unconstrainedoptimization:functionswithtwovariables 10.5 Totaldifferentialsandtotalderivatives 11 Constrainedoptimization 11.1 Constrainedoptimizationandresourceallocation 11.2 Constrainedoptimizationbysubstitution 11.3 TheLagrangemultiplier:constrainedmaximization withtwovariables 11.4 TheLagrangemultiplier:second-orderconditions 11.5 ConstrainedminimizationusingtheLagrangemultiplier 11.6 Constrainedoptimizationwithmorethantwovariables 12 Furthertopicsincalculus 12.1 Overview 12.2 Thechainrule 12.3 Theproductrule 12.4 Thequotientrule © 1993, 2003 Mike Rosser 12.5 Individuallaboursupply 12.6 Integration 12.7 Definiteintegrals 13 Dynamicsanddifferenceequations 13.1 Dynamiceconomicanalysis 13.2 Thecobweb:iterativesolutions 13.3 Thecobweb:differenceequationsolutions 13.4 ThelaggedKeynesianmacroeconomicmodel 13.5 Duopolypriceadjustment 14 Exponentialfunctions,continuousgrowthand differentialequations 14.1 Continuousgrowthandtheexponentialfunction 14.2 Accumulatedfinalvaluesaftercontinuousgrowth 14.3 Continuousgrowthratesandinitialamounts 14.4 Naturallogarithms 14.5 Differentiationoflogarithmicfunctions 14.6 Continuoustimeanddifferentialequations 14.7 Solutionofhomogeneousdifferentialequations 14.8 Solutionofnon-homogeneousdifferentialequations 14.9 Continuousadjustmentofmarketprice 14.10 ContinuousadjustmentinaKeynesianmacroeconomicmodel 15 Matrixalgebra 15.1 Introductiontomatricesandvectors 15.2 Basicprinciplesofmatrixmultiplication 15.3 Matrixmultiplication–thegeneralcase 15.4 Thematrixinverseandthesolutionof simultaneousequations 15.5 Determinants 15.6 Minors,cofactorsandtheLaplaceexpansion 15.7 Thetransposematrix,thecofactormatrix,theadjoint andthematrixinverseformula 15.8 Applicationofthematrixinversetothesolutionof linearsimultaneousequations 15.9 Cramer’srule 15.10 Second-orderconditionsandtheHessianmatrix 15.11 ConstrainedoptimizationandtheborderedHessian Answers Symbolsandterminology © 1993, 2003 Mike Rosser