Alb,06 19fI I k*m R uff 'vrluWjo Q. luv r NEW Math through the Ages A Gentle History for Teachers and Others Expanded Edition A Joint Publication of Oxton House Publishers and The Mathematical Association of America ©2004 by William P. Berlinghoff and Fernando Q. Gouvea ISBN-13 978-0-88385-736-6 hardback ISBN-10 0-88385-736-7 hardback Library of Congress Catalog Card Number: 2003114603 Current Printing (last digit): 10 9 8 7 6 5 4 3 Math through the Ages A Gentle History for Teachers and Others Expanded Edition William P. Berlinghoff Fernando Q. Gouvea A Joint Publication of Oxton House Publishers and The Mathematical Association of America Committee on Publications Gerald Alexanderson, Chair Classroom Resource Materials Editorial Board Zaven A. Karian, Editor William Bauldry David E. Kullman Gerald Bryce Stephen B Maurer Sheldon P. Gordon Douglas Meade William J. Higgins Edward P. Merkes Mic Jackson Judith A. Palagallo Paul Knopp Wayne Roberts CLASSROOM RESOURCE MATERIALS Classroom Resource Materials is intended to provide supplementary class- room material for students-laboratory exercises, projects, historical infor- mation, textbooks with unusual approaches for presenting mathematical ideas, career information, etc. 101 Careers in Mathematics, 2nd edition edited by Andrew Sterrett Archimedes: What Did He Do Besides Cry Eureka?, Sherman Stein Calculus Mysteries and Thrillers, R. Grant Woods Combinatorics: A Problem Oriented Approach, Daniel A. Marcus Conjecture and Proof, Miklds Laczkovich A Course in Mathematical Modeling, Douglas Mooney and Randall Swift Cryptological Mathematics, Robert Edward Lewand Elementary Mathematical Models, Dan Kalman Environmental Mathematics in the Classroom, edited by B. A. Fusaro and P. C. Kenschaft Essentials of Mathematics: Introduction to Theory, Proof, and the Profes- sional Culture, Margie Hale Exploratory Examples for Real Analysis, Joanne E. Snow and Kirk E. Weller Geometry From Africa: Mathematical and Educational Explorations, Paulus Gerdes Identification Numbers and Check Digit Schemes, Joseph Kirtland Interdisciplinary Lively Application Projects, edited by Chris Arney Inverse Problems: Activities for Undergraduates, Charles W. Groetsch Laboratory Experiences in Group Theory, Ellen Maycock Parker Learn from the Masters, Frank Swetz, John Fauvel, Otto Bekken, Bengt Johansson, and Victor Katz Math through the Ages: A Gentle History for Teachers and Others (Ex- panded Edition), William P. Berlinghoff and Fernando Q. Gouvea Mathematical Evolutions, edited by Abe Shenitzer and John Stillwell Mathematical Modeling in the Environment, Charles Hadlock Mathematics for Business Decisions Part 1: Probability and Simulation (electronic textbook), Richard B. Thompson and Christopher G. Lam- oureux Mathematics for Business Decisions Part 2: Calculus and Optimization (electronic textbook), Richard B. Thompson and Christopher G. Lam- oureux Ordinary Differential Equations: A Brief Eclectic Tour, David A. Sanchez Oval Track and Other Permutation Puzzles, John O. Kiltinen A Primer of Abstract Mathematics, Robert B. Ash Proofs Without Words, Roger B. Nelsen Proofs Without Words II, Roger B. Nelsen A Radical Approach to Real Analysis, David M. Bressoud She Does Math!, edited by Marla Parker Solve This: Math Activities for Students and Clubs, James S. Tanton Student Manual for Mathematics for Business Decisions Part 1: Probability and Simulation, David Williamson, Marilou Mendel, Julie Tarr, and Deborah Yoklic Student Manual for Mathematics for Business Decisions Part 2: Calculus and Optimization, David Williamson, Marilou Mendel, Julie Tarr, and Deborah Yoklic Teaching Statistics Using Baseball, Jim Albert Writing Projects for Mathematics Courses: Crushed Cloums, Cars, and Coffee to Go, Annalisa Crannell, Gavin LaRose, Thomas Ratliff, and Elyn Rykken MAA Service Center Oxton House Publishers P.O. Box 91112 P. O. Box 209 Washington, DC 20090-1112 Farmington, ME 04938 1-800-331-1MAA 1-800-539-7323 FAX: 1-301-206-9789 FAX: 1-207-779-0623 www.maa.org ww.oxtonhouse.com Preface This book grew out of a few casual hallway conversations in the Colby College Mathematics Department about two years ago, but its roots are much deeper and older than that. For many years we have been interested in the history of mathematics, both for its own sake and as an aid in teaching mathematical concepts to a wide range of audiences. One of us has used it as a major ingredient in several college mathematics texts for liberal-arts students and as an important part of his contributions to an NCTM Standards-based high school mathematics series. The other has done considerable background re- search in the field, has participated in the Mathematical Association of America's Institute for the History of Mathematics and its use in Teaching, and teaches a course in the history of mathematics at Colby. We are convinced that knowing the history of a mathematical concept or technique leads to a deeper, richer understanding of the concept or technique itself. Unfortunately for teachers and other people with some interest in mathematical history but relatively little time to pursue it, most books on the subject are dauntingly large. If you want some historical back- ground as you prepare to teach quadratic equations or negative num- bers, or if you are just curious about the history of it or the metric system or zero, where would you look? The indexes of most history books will point you to a disjointed scattering of pages, leaving to you the task of piecing together a coherent picture. A topical search on the Internet is likely to inundate you with information, some reliable, some spurious, with little guidance as to which is which. We decided to write a book with your needs in mind. The main part of this book is a collection of twenty-five short historical sketches about some common ideas of basic mathematics. These sketches illustrate the origins of an idea, process, or topic, sometimes connecting seemingly distinct things that share common historical roots. They are preceded by a brief panorama of the history of mathematics, from its earliest days to the present. This provides a skeletal framework of important people and events that shaped the mathematics we know today, and it supplies a unifying context for the separate, self-contained sketches. Of course, the choice of sketch topics was quite subjective; we were guided partly by our own interests and partly by our sense of what might interest vii viii Preface teachers and students of mathematics. If you would like to suggest a sketch topic for the next edition of this book, we invite you to submit it to Oxton House Publishers, either by mail to the address on the copyright page of this book or by e-mail to oxtonhse©mainewest.com. We have made every effort to reflect accurately the historical facts as they are known today. Nevertheless, history is far from an exact science, and incomplete or conflicting sources often lead to conflicting judgments of fact among scholars. Some stories about mathematical people and events have evolved over many years, creating a body of "folklore" with very little hard documentary evidence to support it. Despite their potential to annoy historical scholars, many of these sto- ries - like folk tales in every culture - are valuable, either as allegories or as mnemonic "hooks" to help you (or your students) remember a mathematical idea. Rather than ignore such anecdotes entirely and lose their value, we have opted to include some of the more interesting ones, along with appropriate cautions against taking them too literally. To help you track down more information about any topic that interests you, the section entitled "What to Read Next" is an annotated list for further reading. It includes some pointers to reference works, but its heart is a short "ought-to-read" list of books that we think anyone interested in the history of mathematics probably would enjoy. A note about notation: In recent years, some history books have been using B.C.E. ("before the common era') and c. E. ("the common era") in place of the more traditional B.c.and A.D., respectively. De- pending on which historian one consults, this is either (a) the notation of the future for historical literature, or (b) a passing "politically cor- rect" fad. Without taking a position on this question, we have opted for the notation that we believe to be more familiar to most of our potential readers. Acknowledgments We are indebted to many colleagues from near and far for shar- ing their knowledge and for their forbearance in responding to our sometimes peculiar questions. In particular, we thank mathematics education consultant Sharon Fadden in Vermont, Jim Kearns of Lynn- field High School in Massachussetts, and Bryan Morgan of Oxford Hills Comprehensive High School in Maine for reading and commenting on earlier versions of the book. Special thanks also to Georgia Tobin for creating the TjX symbols for Egyptian and Babylonian numerals, and to Michael Vulis for converting them to PostScript format; to Robert Washburn of Southern Connecticut State University for providing some Preface ix of the material in Sketch 6; and to Eleanor Robson, who generously gave us permission to use one of her drawings of Old Babylonian tablets (on page 63). We are deeply grateful that one of us was able to participate for two summers in the MAA's Institute for the History of Mathematics and its use in Teaching. IHMT helped to transform a lifelong interest in the history of mathematics into a solid base of knowledge on which it was easy to build. Special thanks to IHMT organizers Fred Rickey, Victor Katz, and Steven Schot, to the Mathematical Association of America, its sponsoring organization, and to all the IHMT colleagues - an interesting, varied, knowlegeable, and helpful bunch of people. Many of them answered questions and made useful suggestions while this book was being written, earning still more of our gratitude in the process. Our debt to the many historians of mathematics whose work we read and used as we were writing this book is enormous. Were it not for the giants on whose shoulders we attempted to stand, we couldn't possibly have done the job. We have tried, in bibliographical notes scattered throughout the book and in the "What to Read Next" section, to point our readers towards some of their work. We also would like to thank Don Albers, Martin Davis, David Fowler, Julio Gonzalez Cabillon, Victor Hill, Heinz Luneburg, Kim Plofker, Eleanor Robson, Gary Stoudt, Rebekka Struik, and the mem- bers of the Historia Mathematica group for their answers to our ques- tions. Of course, any mistakes that remain are our own. The Expanded Edition When the original edition of Math through the Ages appeared, some readers who wanted to use the book as a classroom text asked us what sorts of questions we might pose to students. In response to those in- quiries, and with the encouragement of the Mathematical Association of America, we have added 54 pages of Questions and Projects. This Expanded Edition is suitable for a fairly broad spectrum of courses, including many that are designed to prepare future teachers of elemen- tary or secondary mathematics or are part of in-service professional development programs. Moreover, even the casual reader can profit from thinking about some of the questions we pose. The variability in the mathematical backgrounds of potential read- ers of this book invites a variety in the kind and level of questions posed for their consideration. Two pages of Questions and Projects have been inserted after each topical sketch. The distinction between these is
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