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Epilogue

In Japan, we have a traditional tool to produce interesting surfaces one after another, like magic. It is called Nankin-Tama-Sudare, and is a special bamboo blind used for party entertainment. The shapes of the surfaces made with the bamboo blind one after another interest us very much, and the narration of the manipulator is also very interesting.
Before reading this page, you may have thought that surfaces made with modern weapons, computers, are more interesting than ones made with Nankin-Tama-Sudare are. High-tech is wonderful!
These are computer graphics for an end-of-term assignment submitted by second-year students attending the subject "Introduction to Geometry" at the Department of Mathematical Sciences, Ibaraki University. I gave the lectures in the latter half of the 2002 academic year. When I began the subject, more than 100 students wanted to attend it, and the number of students surprised me. There were an insufficient number of computers for students. However, the high-tech classroom at Ibaraki University has a device to make the classroom wider and we could access enough computers. Once this crisis was over, I could start the lectures. The end-of-term assignment was to freely invent a surface with high impression, and to draw it with the symbolic manipulation program Mathematica. To tell the truth, I expected that most students would try to search the Internet and they would submit a copy of the information they found. Among submitted graphics, we have many that are obviously copies. However, we also have some that are more interesting than I expected. Viewing the entire submitted graphics, I note that they are very interesting, and they excite me as a teacher.
As the aim of the subject, I wrote in the syllabus:"As an attempt at mathematical education with computers, we will draw various curves and surfaces with the symbolic manipulation program Mathematica. As the basis of the advanced learning, we understand that there are many curves and surfaces and they are very interesting. We consider why abstract ideas like curvature are necessary." I believe that this aim has been achieved.
We are in the age of personal computers where everyone can skillfully use electronic devices very easily. By considering the possibilities of computers, many people have tried to improve mathematical education. However, many may know that some mathematicians express negative opinions. They claim "Computers are black boxes with unknown principles. We would make human beings who cannot think by themselves, if we use computers in mathematical education." I understand that this is the heart of their negative opinion. Besides, I know that they also claim "Computer graphics have no reality. Only superficial understanding can be achieved with them."
In our assignment, I found that some students made the mistakes described below, since we can still produce beautiful graphics automatically, even if we input incorrect commands. We can notice mistakes easily, if we take the step of considering the principles. Some students don't try to consider them.

  1. For a periodic function, one sets the length of the variability interval not equal to the period.
  2. For some functions like the tangent function, rational functions and the logarithmic function, some values cannot be substituted in the variable. One may obtain a prohibited value from such a function.
  3. One uses a function with tremendously high variation (Example: Sin[10000 x^2]) to draw a surface.

I have corrected mistakes like those above for writing web pages.
As for reality, I believe the generation that has grown up with displays of family computers and cellular phones find computer graphics sufficiently realistic, even though older people may not. Obviously, the word "reality" refers to the psychological aspect of human beings, and it depends very much on the individual.
I have often encountered my computer behaving very strangely in a way that I cannot understand when drawing the submitted graphics to put them on websites. This may be unavoidable, because the computer is doing computations that were impossible for mathematicians before the twentieth century and because the computer is performing very large computations. However, the reason for the strange behavior may be essentially mistakes in programming. I hope that people in developing software continue their efforts to improve the software.
With advances in fixing bugs and further improvements in the ability of computers, the day will come when people the world over will have software for mathematics at home and will enjoy mathematics with it. It will be soon.

References: Tohsuke Urabe, Let's Draw Curves and Surfaces with Mathematica!, Computer & Education, Vol. 13, pp.29-32, 2002, Council for Improvement of Education through Computers

04 March, 2003 Tohsuke Urabe

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