PROBLEMS BOOK TO ACCOMPANY Tamara Todorova Problems Book to Accompany Mathematics for Economists Tamara Todorova ® JOHN WILEY &' SONS, INC. ACQUISITIONS EDITOR Lacey Vitetta MARKETING MANAGER Diane Mars EDIORIAL ASSISTANT Emily Mes SENIOR DESIGNER Jim 2'Shea PRODUCTION MANAGER Micheline Frederick PRODUCTION FOITCR ‘Amy Weintraub This book was printed and bound by Courier Westford. The cover was printed by Ca.rier Westford This bookis printed on aid free paper. « Copyrign: ©) 201 john wiley & Sons, Inc. All rignts reserved. 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Upon completion of the review period, please return the evaluation coxy to Wiley. Retura instructors and ‘ree ct charge return shioping label are ava lable at ww suley.com/gofretumlabel, Outside of the United States, pleose contact your lozal representative Lbrary of Congress Cataloging in Publication Data: ISBN-13 978-0-470-59181-9 Printed in the Jnited States of Americe wessesssza Table of Contents Matrix Algebra 2, Comparative Staies I: Parti Derivatives 3. Comparative Staties I: Differentials ne Variable 4, Optimization of Functions of §. Fxponential and Logarithm Functions 6. Functions of More than One Variable Constrained Optimization 9, Simple Diffecential Equations 10, Simple Difference Equations 1, Advanced Differential and Difference Equations electronic website: 12, Inroduetion to Dynemie Optimizatior The Caleulus of Variations electronic website: www wiley comical 61s com‘collegeitodorova 70 rodorova Detailed Table of Contents Chapter 1: Matrix Ak ~ ransposes und inverse, nansingulariy ua mais, ddterminas, mats inversen, Cram’s rule, Cass method, market equlirium analysis, Seyesian rational-income model, Leoatiesiapu-ouput model, problems. Jura near mo Chapter 2: Comparative Staties I Partial Derivatives derivative, rules of ferentiation, iteremiation of functions of more thar one vavahle, inverss-function rule, partial derivatives Jacobian detereinans, problems Chapter 3: Comparative Staties Il: Differentials point elsticity.pstal and tral A ferentials, es af dilfereils, total derivatives af composite functions, implieit-antion rae inns function thea, aeneral-Funeion mocels ~ market equilisrcm: model, IS-L model, protlems Chapter 4: Optimization of Functions of One Variabl eriative test, polit mission, eubie cost function, eubie prot Funston, ah derivative test fr relative extremum, problems Chapter S: Exponential and Logarithmic Functions exponcntal factions, the ntanbore. meres compounding, ineanuarcous rae cf growth, daunting, logaitbns ules of logatthes, ithe “unctons, base conceiscn,de-isatives oF expaneatial sad logaithm funetions,eptimal timiag ate of geewth af composite functions, port slastcity revisited, prablems Chapter 6: Functions of More than One Vari three and mono variables, ch fire, inp functions of ‘arable quadratie forms, esnitiems For optimization withoul consti, ferstic-ool test fr sign deiniteress, tious and nlinarket fe, inp ins and onparasive satis asposts of optimizatioe, problems Chapter 7: 19 Lagrange-maliplior msthod,»-varuble and rmukiconsraint case, conditions for optimization with consists, utility maximization, Shusky ‘iin inl constsints, lotapgencs nets, Cold-Dowglas peraduct on Fusetion, Slasiigy of substation, CES prouction funtion, problems Chapter 8: Integration —indefinice integral rules of integration, dete ineptsls, isproper integrals investment and capital formation, consusnet and areducer surplus, probability anc detinite inearls, present value of a cashflow, Dantar grower mod, problems ter 9: Simple Differential Equations —frst-onler linear differential equations with constant coefficient and constant term, dynamie model of market pice the case ‘coefficient and variable ter act diferamtal equations, integrating factors, separation of variables, Bemoulli equations, phase ciggroms, Solow growih model, problems ‘Chapter 10: Simple Difference Equations ~frst-onler difference solving, dynamic stability of equilibrium, the Cobweb model, pro Chapter 11: Advanced Differential and Difference Equations ~ second Aiferenval equations the Arve-Pratt measure of risk aversion, rearket equilibrium wit price expeciatons, the relationship between inflation acd unctaploymient, higher-order differental ‘equations, secand-ordereifference equations, muliplie-accelratar model, inflation and uemployerent in discrete time, higher-order diference equations, problems Chapter 12: Introduction to Dynamic Optimization: The Calculus of Va introduction to dynamic optimization, the eae ‘cost-minimizing firm, constrained dynami opti problems tions tion, Ramsey growth ization, a glimpse of optimal contol theory Preface his aupplement i itended to complement any couse in quanialive msthuds in exoromice, mathematical ‘eonamies for undergraduate student or inlrductory malhomatical economics for grate stents, The Key snd srengthen the theory they have leat from standard exthooks ia mathematical evonomics. The book supalements sry ofthe mest videly used texts, such as Mathomatise for Economists by Cal Simon ed [Caurence Bhime end Fundamental Methods of Shthematcal Exonamics by Alpha Chi ‘While these books are predominantly theoretical xs, the problens book i a practice text iustrating a a umber ef matiematial tools ob ‘applied in econcmics. Al problems are economic applications, and no problem s purely mathematical without elevance to evo. In fc, nan probes eas be sta a itaple conomic models that challeige student hinking an knowles, While non aerate textbooks i he ara sess the math theory and Musa it with sone economic aplication, dis buck iss sch an economics bok es tsa math book, For completeness, sh: Ihereticalsuaraaries uf Us relevant Urey ae fdesiptions of econ ecpleaions ae pid in (ve hen cee chapter i eine ste to he essentials ofthe subject, However, ee sutetivalsumamaes ave only prefory aera, seoralary Wy the asin purpse of te book, ith elinw uriginaity uy put except in we sections, The thew ‘nly meant orient the renders before they plunge in he rublems, which I have tried to mae ws wide ging as possible, I ear the problems and solutions asthe essence othe Bock ad the justification fort The book is designed for sucenis af economics who are taking mathematical economics as par of thee ‘disaton, About 70 persent ofthe esomomics conten, herein, is drawn fom microeconomics, and the est from macroeconomics. Thus, courses in intemede micto-and macroeconomics are sable prerequisites for this book. fist course in calelus is sirable as well, An essential aim ofthe book isto popularize the subject of maematical economics sad make it more accessible to beginning eonom ss, While a large numberof students around the world ae ntigved by ‘sonomies nd finance, particularly amid glabal nancial and economic ers, ewer ae eager lo pursue scmamies beens of 1 math "hey WoLId ive fo daa ecenmmies majors, Hanl-core mattematies bordering fon the graduate evel scares a great man students and deters them from slyng economics. This book redices the intimidation with math und helps make economics # mote interesting ard upproachable subj While the problens book may be use by heyinn ng graduate students of ecoromics i: isnot perfsedy suited for them, Rather, at his acvanced level, students might use the s00k as reference gue to reltesh some ost knowledge. Therefore, he book is appropriate forthe masters level and peshaps arious quantitative fools wo ther feds of study may also use the Book. Yet, tis oka perfect substitute for a ook in applied athena for business 0: Finacial mathematics, Nester i La sibs Fora suse i intermediate microeconomics, although many of te robles i this book are drawn om sich a course fom: Wook economists was writen a a response oan insuticency inthe etd ef matnematical economics 0 appropriate dy (aos and exercise bonks, Students af economies ac robust hemework-ype problems with which o fest ther knosledge. Asa professor Ihave found att bea Serous handicap my leeching. My students have hac no substan! learring sds or tools, and hence have shed foc a book hat gives exercises tthe level of exams in the course, This resulted inthe design ofa rember of problems, the prodost of years of wark, The proms ars eae for sudents to work with as they Closely follow the tacory covered inthe beginning of seh shaper. Many problems expand onthe ceoncmic tnadee and apliestions proviced inthe thsoretical pat, Problane are aranged thematically tts wit) che jr oyes ard moving tothe move challenging ones, Sues can ty to solve a yusblem without Inoking is slution ~ this ie wha call acive selving. Only aftorvard should they Took up the slution and compare it With their own results. Otherwise, they would be tempted to fallow the solution pasvely and without mus | Understanding | Interns of eentent,the problems book cavers the most essential applications of mthematss in eecnomiss ‘matrix algebra, exponential functions, logarithmic functions, unconstrained and constrsined, optimization, end integral calettus The last part of the book diac1scedifersntial an difference equations, string with irs-order eqtions nd moving t higher-order anes, Thes last topics are more chal enging for 1rdergras, and there acl tine to dacust them ina ne-semester couse. Vet they ar included for those studi taking rigorous math eourscs or double-msjoring in mathematics and economies, a well To some beginning graduate students who want to brush spon thei enowledge of differen ealeuius. Tot also salle with ‘optimal contol theory, These lst opis are discuss: in bom chapters loested a the Wiley website [thank my editor, George Lobel, who believed inthis project an gave mca helping band. is ski sidance and editing ofthe book helped me overcome numercus problems and my inexaerience as an author, 1 am also thankful to Constance Acler, Emily MsCie, Lacey Vite, and Amy Weiatrau from Wiley Blackwsl for ecordiaating the proces of book aepatation an! assisting my work. Secial thanks go to Amy ‘Weintraub who was oy reduction Elior ud whe fllewed br dealine sty. an ndcbied to Joan Diesel for pootieading + manscrpt fl f extn and yatsbles, Lalo tank te illo reviewers w rose help eae ented tpesernnt ne Lok: Steven Aner (Roxseve iivesiy) Mak Arvin (Trent Universiy, Cad), Manica Costa Dit (University College Lamon), Bests Gross (University ‘of California, Berkeley), Karee Isl Joins Hopkins University, Mins Batre Lute [University ‘NonlFlorca), Wing Suen (University of Heng Kong), Rosia Wooster (Porn State Universi), nd Wendy Wu (Willi Laurier University) Baral Ramachandran, who i my sp re mich inspiration in writing the bok. He was always there io advise me ané encour ‘omens of isess und disappointment. Lar also truly grateful to three work-study’ stents of mine ‘Yordansa Kestova snd Moin Miley meticulously solv! and eorested problems for me, the fs forthe etry | version ofthe bok ard the second forthe ae. [express my Thank to A exandru Androni, one of myst ‘work-say students, who gave me he ides a writing My problems electronically. Alex Was the Fist 9 write | those in Mitossft Equation, This ulate brought me tothe Kea ing the book, I shoul also mention ‘hat all my’stadens raking Quaniative Methods in Econoenics with me athe American University in Bulgaria reeoive my appreciation, The students fom te ls fue Years helped re the mast asthe book was ested ‘hem numerous ies. Finally, 1 vish to tank my Family, my mom and ia, who had patience the etn writing ofthe book. dedicate this book to my daughter Tayana, who grew aang with ihe book and was livered several moras Before the manuscript ws complete Tamara Todorova >on I Suggested Readings 1, Arvo, Kenneth J, Hollie 8, Chenery, Ragichs S. Minhas, un Robert. M, Solow. “Capital Labor bsttton and Eeonontic Etexney.” Review of Economie i Sansfioe Avast 1961}: 225 280, 2, Baldun, ete, Jemes Beaded and Rober Tumor Akathersorial Ezonomice aston, MAS Thomson Lasring, 20 Blanchard, Olivier Macroecomoe 1. Chiang, Alpha C, Fuerst Til I, 198. ed. Enplowood Clits, Nl Pearce Hall Inert ons, 2000, Methods of Muthematcel Economics. 3 Now Yorks Mere S. dee Fount, Angel Mahemotia! Movin und Macels for Boowonits Catsidge: Cambridg Universily Press 200 6 sey, “Capial Expansion, Rate if Growth, sd Fnplytnent,” Eeamomet i, Api 1946 75 reprinted im Domar Ess inthe Phe ef Beaman Groth. Oxted iver Pas Dixit, Avinash, Optimization bx Eoonaaie Paory. 2% of, Ostoré Lniveity Pres, 1990. 8. Bowing, Edvard T. ntodheton vo Mathrsncc!Lcowomis, ix Schur’ Outline Serie New Yale MeGiaw-Hil, 192, 9. Inoue, fa, Mathematics for Bonnie ane Busines. od. Englewood Clits, NI: Prete Hal, 206, 10, Keyes, John M. The Goneral Thay af Engparment Stare ad Mone, Aachen, NV: Prometheus 11, Leona. Danie. and Ngo Yan Lang, Optima! Canin Ther ed State Optician in Sconce Cambridge: Carbide Universiy Press, 1998 Leontil, Wassily W. tnpnt-Onfpus coments, 2°, New Vers: Orb University Pros (986, 15, MaeColell Andrew, Micisel D. Whinetn, an Cory, Gen, Micnaenonomie Teor: Ost University Press, 198 14 Nichotsoa, Walle Pres, 382 15. Penfieon, Malcolm, ard Nicho'as Rau. Mathias for Beonomies Mi Univesity Pen, 2001 snore Theory: Base Principles and Extonons, Yort Worth, TX: Dryden 6, Pili, Alla “The Relationship betwesn Unemployoien: aud the Ret of Change of Me Wage Rakes in Usa! Kingbnn HGT=1957" Faveenacs Neve 1958) 283-299 17 Rainville, Bal Davi, Philp E, Bolics, ad Rigid Baloo, Flementary Dievental Equations 2h ed. Lpper Sie iver, i Prentice Hal, 1996 18, Suruekon, Pal. Foundations of Economic Anais, Caubeidye, MA; Harsad Univesity Press, sr, 19, Silberberg, Eugene, and Wing Suen, The Sinem af Boronic" A Masons Arie. Now "York: MeCi-iiIrvn, 200 Simon, Carl und Lawrence Bume. Mfariomaries jor eanomsts. New York: W. W. Nort 19, Solow, Rober M.A Contribiton 29 she Theary of Eeomosis Grth.” Qrarter'y Jaw Foote (Ferry, 956) 65-9 22, Solow, Rebert M, “Technical Change and the Agaregate Production Function.” The Review Economics end Statistics, 3: 90.3 (August 1957) i 23. Siilta, Joseph E.,and Car E. Walsh. Economics 3 ea. New York: W..W. Norton and Compan 24, Sydsueer, Knut, and Peter Hammond, Esientval Mariersanes for Beononte A “od Englewond Cis, NJ: Petes Hal, 2906 5, Varian, Hal, ieraeconomi nays, New Vonks W.W., Norton, L984