History

Reading Euler's Introductio in Analysin Infinitorum

 Introductio in Analysin Infinitorum Title Page

Noted historian of mathematics Carl Boyer called Euler's Introductio in Analysin Infinitorum "the foremost textbook of modern times"[1] (guess what is the foremost textbook of all times). Published in two volumes in 1748, the Introductio takes up polynomials and infinite series (Euler regarded the two as virtually synonymous), exponential and logarithmic functions, trigonometry, the zeta function and formulas involving primes, partitions, and continued fractions. That's Book I, and the list could continue; Book II concerns analytic geometry in two and three dimensions. The Introductio was written in Latin[2], like most of Euler's work. This article considers part of Book I and a small part. The Introductio has been massively influential from the day it was published and established the term "analysis" in its modern usage in mathematics. It is eminently readable today, in part because so many of the subjects touched on were fixed in stone from that day till this, Euler's notation, terminology, choice of subject, and way of thinking being adopted almost universally.

Descartes and La Géométrie

 Rene Descartes 1648
René Descartes in 1648.

Everyone knows that Descartes founded analytic geometry with his little essay La Géométrie, published in 1637 as an appendix and proof-of-concept for a work on philosophy, Discourse on Method. As always, the story is more complex and interesting than that. The canonical modern work in English is History of Analytic Geometry[1] by Carl Boyer, which includes this from his much-admired antecedent Gino Loria (1862-1954):

In truth, whoever studies thoroughly the treatise of Apollonius on Conics must confess the profound analogy it bears to an exposition of the properties of the curves of second degree by means of Cartesian coordinates; not only do the fundamental properties employed by the Greek geometer to distinguish the three curves one from the other translate into the canonical equations of the same in Descartes' method, but many of the reasonings given, when translated into the ordinary language of algebra, answer to elimination, solution of equations, transformation of coordinates, and the like. What we would however seek in vain in the Greek geometer is the concept of a system of axes, given a priori, of the figure to be studied.

Wisconsin State Journal Death Spiral

 State Journal Gay Marriage Aug 27 2014

The predecessor of the Wisconsin State Journal was founded in Madison in 1839 when Wisconsin was a rude territory, and as Whigs they endorsed William Henry Harrison in 1840 - Wikipedia has a great write-up on this paper over the years. The State Journal played a heroic role as anti-slavery crusaders in the Glover case in Milwaukee in 1854, helping to defy the Fugitive Slave Act and spring recaptured slave Joshua Glover from jail (I remember reading about it circa 1970 in Eric Foner's Free Soil, Free Labor, Free Men and feeling oddly proud of my hometown paper). Like many Whigs, including Abraham Lincoln, they became Republicans and duly endorsed the Great Emancipator. They became a progressive and even muckraking organ in the period 1890-1916. Since then they've been a reliable right ring mouthpiece, recent timid attempts to transcend that heritage notwithstanding. They were virulent jingoists in the First World War, scurrilously attacking Fighting Bob La Follette. They were shameful McCarthyites from the get-go, endorsing him in every one of his state-wide campaigns, including the first run for Senate in 1944, when they were one of four papers to do so and the only one outside the Appleton area. They broke their workers' strike in 1977 (I was on the board of the strikers' paper, the Press Connection).

Newton and Kepler's Laws

 Issac Newton 1689
Issac Newton in 1689, at the height of his powers (age 46).

Nature and Nature's Laws lay hid in Night:
God said, 'Let Newton be!' and all was Light.

- Alexander Pope

Kepler's laws of planetary motion are:

1. The orbit of a planet is an ellipse with the Sun at one focus.
2. A line from a planet to the Sun sweeps out equal areas in equal times.
3. The square of the time of revolution of a planet is proportional to the cube of the transverse axis of its elliptical orbit, with the same constant of proportionality for all planets.

Intersecting Chord Theorem for Ellipses

 Brackenridge Figure 5.12
PG and DK are conjugate diameters and PG bisects chords QQ' and DK. Book 1, Proposition 21 of Apollonius's Conics implies that (PV×VG)/QV² = PC²/DC².

This image and caption are from J. Bruce Brackenridge's The Key to Newton's Dynamics: The Kepler Problem and the Principia[1] (p 114). Newton used the result to prove that elliptical orbits imply an inverse square law. Note that PG and DK are "conjugate diameters" of the ellipse, meaning that PG is parallel to the tangent at D (or K - the tangents at D and K are themselves parallel). The situation is symmetric, so it is equally correct to say that DK is parallel to the tangent at P (or G). As the diagram suggests, all the chords parallel to one conjugate diameter are bisected by the paired congugate diameter. Conjugate diameters are an old concept going back at least to Apollonius; modern too since they map to perpendicular diameters of a circle through an affine transformation.

Archimedes and Pi

 Archimedes by Fetti

Archimedes is one of greatest mathematicians of all time (his name \( A \rho \chi \iota \mu \acute{\eta} \delta \eta \varsigma \) means "master of thought" in Greek). He lived in the third century BC in Syracuse in Sicily (287 BC - 212 BC), then an outpost of Greek civilization. He has been highly regarded since his own time, which is perhaps why much of his work survives. Not all of it though, The Method being turned up in 1906 in the Archimedes Palimpsest (see Wikipedia's write-up as well). What survives is sufficient to measure his stature; he plainly anticipated calculus and knew as well as anyone today what a proof is, heir to the great classical school of Greek mathematics and Euclid. There are a few stories. One is that he was relaxing in his bath pondering the question of whether the king's gold crown had been adulterated and in an instant conceived the notion of buoyancy that bears his name. He was so excited, he jumped up and ran naked through the town shouting "εὕρηκα!" (Eureka - I have found it). It does seem fanciful, but is based on his surviving work On Floating Bodies.

Gauss and the Fast Fourier Transform

 Gauss Stamp

The Fast Fourier Transform (FFT) is a modern algorithm to compute the Fourier coefficients of a finite sequence. Fourier will forever be known by his assertion in 1807 that any function could be expressed as a linear combination of sines and cosines, its Fourier series. "Any" was a little ambitious, counter-examples coming to the fore in due time. A fair amount of mathematics from that time to this has been devoted to refining Fourier's insight and studying trigonometric series, a subject that led Georg Cantor to founding set theory. Piecewise smoothness is sufficient for pointwise convergence on \( [-\pi, \pi] \):

\[ f(x) = {a_0 \over 2} + \sum_{j=1}^\infty \left( a_j \cos jx + b_j \sin jx \right), \]

Calendar

 August 2013 calendar

My original calendar program was on the Casio fx-3600p calculator in 1980 or so - my first programming venue and exercised partly in spare moments when driving truck out on the route; a precursor mobile device you could say. My buddy Dave got me started. I might have scarred myself permanently though. The transition from math to software engineering is always tricky, considering that there are many commonalities, but just as important differences to snag the self-taught and perhaps obstinate and all-too-confident mathematician (perish the thought). The 3600 had this bizarre little macro language providing for a trade-off between memory and program size. You could have (say) fifty memory locations and 400 instructions or twenty locations and 600 instructions. They're really variables of course, but the memory locations were designated K0 through K19 or something.

The Chinese Revolution

 Mao Tse-Tung and Chu Teh Two works by Americans are canonical references for anyone who really wants to understand this monumental, cataclysmic event:

  • Red Star over China, by Edgar Snow
  • Fanshen, by William Hinton
I

Edgar Snow worked as a journalist in China as a young man and traveled to Yenan, the remote base of the Chinese Communists, shortly after the Long March brought them there in 1935. This was a period where little to nothing was known of Mao Tse-Tung and his associates or the Communist movement in China, extensive as it was. There had been a number of Soviet areas in south China governing millions of people in the early thirties - it was because of their encirclement by the Chiang Kai-shek forces of the Kuomintang (KMT) in the fifth anti-Communist extermination campaign that the legendary Long March was necessary to escape the old bases and relocate in the northwest at Yenan in Shaanxi. Snow interviewed Mao and other top leaders fresh from this epic campaign; till that point and long after, his account was the only one known in the West. He somehow got Mao to open up about his own background, something almost irregular among these self-effacing revolutionaries.

Battle Cry of Freedom

 Abraham LincolnFondly do we hope -- fervently do we pray -- that this mighty scourge of war may speedily pass away. Yet, if God wills that it continue, until all the wealth piled by the bond-man's [slave's] two hundred and fifty years of unrequited toil shall be sunk, and until every drop of blood drawn with the lash, shall be paid by another drawn with the sword, as was said three thousand years ago, so still it must be said "the judgements of the Lord, are true and righteous altogether."

-- Abraham Lincoln (March 4, 1865 at his second Inauguration)

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