Piazza Class page.
Week 2: 24 January 2022.
- Opening Remarks:
This would be a good time to decide on the book you plan to review for
your Book Review.
A prominent 20th century British mathematician described the Greeks as `fellows of another college'.
Their accomplishments and methods remain valid and inspiring to many, even after over 2 millennia.
This illustrates a major feature of mathematics, which sets it apart from other human endeavors:
Mathematics is additive.
While topics may go in or out of style and what is important may change over the generations, the discoveries of the past remain valid
and they form part of the foundation of current work.
I believe that Stillwell starts with the Greeks because of their modern outlook (hence the above quote), they were the
first to use the deductive method and require that mathematical truths be proven.
They also used abstraction (think Platonic ideals, or potentially infinite Euclidean lines, or...)
There is an enormous amount written about Greek accomplishments in mathematics and culture.
Stillwell presents a selection of their more elementary accomplishments.
Chapter 1 introduces us to two of the great theorems in mathematicians: First, the Pythagorean Theorem. Stillwell does this justice, as
it brings together geometry, algebra, and numbers.
Famously, there are many distinct proofs of it, and several of the more elementary are given (note that the proofs in Figures 1.7 and
1.8 require the unproven fact that area is additive: The area of a disjoint union is the sum of the areas.
This innocent statement hides remarkable subtleties, check out the Banach–Tarski paradox and Hilbert's third problem.
The second is of course, the irrationality of the square root of 2, which revealed that completely new class of numbers must necessarily
be, and upended the (then) current notions of number.
Chapter 2 is a sketch of Greek geometry, and the start of the deductive method.
It is worthwhile to reflect on the profound influence of Euclid on Human intellectual culture.
The discussion of curves in Chapter 2 of Stillwell is informed by advances made nearly two millennia after the Greeks;
namely René Déscartes' cartesian coordinates in the first half of the 17th century.
- Reading:
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Chapters 1 and 2 of Stillwell.
In your readings of Stillwell, I'd like it if you could include reading the exercises, as well as the text.
The historical notes at the end of the chapter provide some interesting color about the lives of the protagonists; they are likewise
worth reading.
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While we appear to have a great understanding of Greek mathematicians and their mathematics, this knowledge has not come to us as
easily as, say our knowledge of 19th century physicists.
To appreciate this, please read the St. Andrews page
How do we know about Greek mathematics?.
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In Plato's dialog Meno type "inquisitive" into your web browser's text search window to get
quickly to the scene with the slave boy. Read that part of the dialog.
- Try your hand at Euclidea, adn on-liine straightedge and compass constructor.
- Assignment: Due Monday, January 31, 2022. (HW 2 and Concept Quiz 2)
The quiz (on Gradescope) is four exceptionally short questions with even shorter answers that you need to take after you have
completed the reading.
It is OK to discuss the homework among yourselves.
Some of these problems will require you to find other material than just what is in the readings.
Here is a .pdf and a LaTeX source of the assignment.
To hand in: We are using Gradescope for homework submission.
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Who was the British mathematician who made the remark at the top of the page?
What do you think he meant by this?
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Greek mathematics deeply affected at least two US presidents.
Research and write about the influence of Euclid and Pythagoras on US Presidents (There is one US president for each of these
Greek mathematicians).
For each, there is at least one very interesting detail/story. Find it, and describe it.
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What were the three geometric problems of antiquity? (Sometimes called the Three Classical Problems).
For one, describe it origins (at least the best that you can find out).
Were any solved by the Greeks (in any fashion)?
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Do Exercise 1.3.4 in Stillwell.
Note that t is the vertical coordinate of the point where the longish secant meets the vertical axis.
How is this related to the `world's sneakiest substitution' from Calculus?
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Do Exercise 1.4.2 of Stillwell. This is one of the easiest proofs of the
Pythagorean Theorem, and is often presented in elementary geometry classes.
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Do Exercises 2.4.1 and 2.4.2 from Stillwell.
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Do Exercises 2.5.1 and 2.5.2 from Stillwell.
Last modified: Thu Jan 27 18:55:47 CST 2022 by sottile