A Differential Equation from a Parallel Universe

By Julio César Martínez Romero

Grade 9 was the most boring year of my life. I remember sitting in front of a map, trying to memorize the names and locations of all the eighty-five Mexican rivers. I sat there, fearing the exam where I would have to face an empty map of Mexico, and I would have to draw those rivers and write their names . . . and geography was the fun subject. Other subjects were terror stories. I did not understand a word of trigonometry. That subject was like watching an endless parade of odd names traveling on meaningless formulas. When the afternoon was warmest and we were all drowsy, our physics classes took place. We were fifty fourteen-year-old students in a smelly and suffocating classroom, watching a teacher copy a textbook on the blackboard, expecting us to copy it on our notebooks. This was my life when I was fourteen. If your life is not very different, then I wrote this book for you. Maybe you also find the mathematical exercises so absurd and boring that there is no way that you are going to spend your weekend studying for an exam. I used to be fourteen, and I was not very different from you. Then, I discovered algebra. I hope that after reading this book, your concept of mathematics might change too.

• Language: English
• Publisher: Palibrio
• Release date: Apr 12, 2017
• ISBN: 9781506519951

Julio César Martínez Romero

Teaching mathematics is my life. I have been a mathematics teacher since 1985. I have taught students in their 5th and 6th grades of elementary education, in junior high school, in high school, in bachelor and doctorate levels. I have been teaching Differential Equations at the Undergraduate Program on Genomic Sciences of the National University of Mexico since 2006.

Book preview

Contents

Part I.   Parallel universes

Part II.   A Universe of Ranchers and Mammoths

Part III.   An interference. A universe of ocelots

Part IV.   Back to the universe of ranchers and mammoths

Part V.   A universe of space travelers

Acknowledgements

I thank Daniela Carrera Millán, Gilles Figuier, and Noelle Ann Mabry for their kind participation in this book. I also thank and acknowledge the work of Ismael Álvarez León, who kindly took and donated the cover photograph and of Ron Polk for all the other photographs included in the book.

Note on the illustrations

An actor’s performance in a silent film from the 1920’s consisted in a collection of dramatic face expressions. A hundred years ago, those gestures evoked deep emotions in the public. On those days, fourteen-year-old youngsters were thrilled by the films that they watched in a movie theater.

A century of films has changed the definition of visual impact. Nowadays digital images deliver the most awesome experiences on every HD film and videogame. Teens are not easily surprised any more. Their eyes do not stop, not even for a moment, in the 3-D rendering of an image, complex and full of details. The visual environment provokes no thoughts, no inquiries. This book was written for fourteen-year-old youngsters who demand the highest quality of video. This is the reason why I decided that I would not try to fulfill their expectations for image quality and I would resort to an outdated style of pictures, those that moved youngsters and made them dream, reflect, and wonder a hundred years ago.

Hopefully, present day teenagers will look at the illustrations shown here and ask themselves what kind of images they are. Why are these photos here? What is their meaning? What is their relationship to this book?

Maybe the eyes of a youngster will be fixed, at least for a moment, on an illustration. Will it catch a youngster’s attention? If teenagers are now used to high-tech digital imagery, let me give them the visual environment that teens of other time would find familiar. Maybe youngsters today will dislike the photographs presented here, but then again, at least they will have noticed them and, in the best scenario, questions might have arisen in their young minds. Questions stir more brain activity than indifference.

Introduction

There was a time, not long ago, when you were thrilled to spend a Sunday afternoon playing cards with your grandparents. In those times, you loved to go with your granduncle to pet baby animals to the zoo farm on Saturdays. You begged your father to take you to the wild animal park, or to go rowing to the lake.

Nobody expected then, that on a certain day a dormant gene would awaken and it would trigger the production of huge amounts of hormones. These hormones would upset every balance and disturb every aspect of your life. Your brain would be gravely affected. You would be overcome by emotions, thoughts and fears that you would have never imagined before. One day you would be saying the unthinkable and doing the unimaginable. You knew that you were the same child that you used to be, because you shared all his/her history and memories, but his/her likes and dislikes,