Renaissance Europe Regiomontanus
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Renaissance Europe Regiomontanus • Born near Königsberg in Lower Franconia in 1436. • Johann Müller • Johannes Germanus • Johannes Francus • Johann von Kunsperk • Regio Monte (“royal mountain”) • Regiomontanus • Johannes de Monte Regio Regiomontanus • Studied under Peurbach, who was writing a corrected translation of Ptolemy’s Almagest. When Peurbach died young, Johann took over this task. • Became friends with Cretan, George of Trebizond, a Ptolemaic scholar, whom he later criticized for errors in interpretation, as “the most impudently perverse blabber‐mouth.” Regiomontanus • Traveled extensively. • Was asked in 1467 to be librarian to the Royal Library of Hungary (the king had just returned triumphant from a war with the Turks, brought back a number of rare books). • Cast the horoscope of the King, predicting that he would not die, and when it turned out that way, was lavishly bestowed with gifts. Regiomontanus • Returned home in 1471. He settled in Nürnberg, which had a printing press. • First publisher of mathematical and astronomical books for commercial use. Also published some very popular calendars. • Was asked by Pope Sixtus IV to come to Rome and help revise the old Julian calendar, which was out of tune with the seasons. • He died there on July 6, 1476. Regiomontanus • We don’t know cause of death, but one tradition is that he was poisoned by the sons of Trebizond, the “most impudently perverse blabber‐mouth.” • Another tradition is that it was a passing comet. Or a plague. Take your pick. Regiomontanus • Wrote De trangulus omnimodis, or On triangles of every kind. It had five parts or books, and was modeled, of course, on the Elements. • Finished in 1464, but not published until 1533. On Triangles of Every Kind • Book 1: Basic definitions of quantity, ratio, equality, circle, arc, chord. • “When the arc and its chord are bisected, we call that half‐chord the right sine of the half‐ arc.” • A list of axioms, followed by 56 theorems, most geometrical, solving plane triangles. Theorem 20 uses the sine to solve a right triangle. On Triangles of Every Kind • Book 2: The Law of Sines, stated literally rather than with symbols. Used to solve SAA and SSA cases (thus dealing with the “ambiguous” case). • Area of triangle in terms of two sides and included angle: • Used sines, cosines (= sine of complement), and versines (1 –cosine). On Triangles of Every Kind • Sines and cosines were still defined not in terms of right angles, but in terms of line segments associated with a given arc in a circle of fixed radius. • The fixed radius was usually a power of 10, or 6 times a power of 10, with the powers getting larger in later books so as to avoid decimal fractions. On Triangles of Every Kind • Books 3‐5 deal with spherical geometry and trigonometry, as a prerequisite to astronomy. • “You, who wish to study great and wondrous things, who wonder about the movements of the stars, must read these theorems about triangles. For no one can bypass the science of triangles and reach a satisfying knowledge of the stars. A new student should neither be frightened nor despair. And where a theorem may present some problem, he may always look down to the numerical examples for help.” Ephemerides • Regiomontanus published his Ephemerides in 1474. • It contained tables listing the position of the sun, moon, and planets for each day from 1474 to 1506. • Columbus took it with him on his fourth voyage, and famously used it to predict the lunar eclipse of February 29, 1504, to the amazement of the hostile natives. Fra Luca Pacioli • 1447‐1517 • Local education, then became a Franciscan Friar. • The “Father of Accounting.” • Introduced for più and meno, or plus and minus. Fra Luca Pacioli • Summa de arithmetica, geometria, proportioni et proportionalita (1494) • Shamelessly borrowed from earlier authors. It laid out the boundaries of contemporary mathematical knowledge. • Ended with the prediction that the solution (by radicals) of the cubic equation was impossible (like the quadrature of the circle). Which leads us to our transitional character, Scipione del Ferro. • Born 1465, but did his important work with the cubic between 1500 and 1515. • Didn’t publish, but closely guarded his work. Depressed Cubic • By making the substitution for an appropriate value of c, any cubic can be reduced to a cubic without a second degree term. Thus it will be of the form: • , with b and c rational numbers. • But in 1500, we only liked positive rational numbers, so there were actually several forms of this “depressed” cubic. Depressed Cubic • • • • • del Ferro solved this depressed cubic in at least one, possibly all, of its forms. Scipione del Ferro • When he died, his papers containing this solution were left to his son‐in‐law Annibale della Nave, and to one of del Ferro’s students, Antonio Maria Fiore. • Fiore intended to use it. <cue ominous music> More on the Cubic Later • But first, some other important mathematics. The Abacists vs Traditionalists • Dear Professor: You keep on using that word. I do not think it means what you think it means. • Abacists were abacists in the sense of Liber Abaci, that is, they used the Islamic tradition of decimal numbers and algorithms, and eschewed counting boards in favor of pencil and paper. The Abacists vs Traditionalists • The Abacists won, but it took a while. • “But what if you were stranded on a desert island without paper? Then you’d wish you’d studied how to use a counting board……” Rafael Bombelli • Rafael Bombelli (1526‐ 1572) • His family had been out of favor with local leaders. • Lived in Bologna and was tutored by an engineer/architect. • Worked as a hydraulic engineer, draining wetlands. Rafael Bombelli • While waiting for a certain project to recommence, decided to write an algebra book. • Published in three volumes (two volumes of geometry that were to follow were not published) Rafael Bombelli • Wrote down rules for negative numbers: • Plus times plus makes plus Minus times minus makes plus Plus times minus makes minus Minus times plus makes minus Plus 8 times plus 8 makes plus 64 Minus 5 times minus 6 makes plus 30 Minus 4 times plus 5 makes minus 20 Plus 5 times minus 4 makes minus 20 Rafael Bombelli • Wrote down rules for computing with complex numbers: • Plus of minus times plus of minus makes minus [+√‐n . +√‐n = ‐n] Plus of minus times minus of minus makes plus [+√‐n . ‐√‐n = +n] Minus of minus times plus of minus makes plus [‐√‐n . +√‐n = +n] Minus of minus times minus of minus makes minus [‐√‐n . ‐√‐n = ‐n] Rafael Bombelli • Notation: Modern Bombelli Printed notation 5x 51 5x2 5 2 46 Rq 4pRq6 3 2 0 121 Rc 2pRq 0m121 François Viète François Viète (1540 – 1603) was a French lawyer who worked for kings Henri III and Henri IV as a cryptanalyst (a breaker of secret codes). François was born a French Protestant (Huguenot), and when Henry of Navarre, also a Protestant, came to power, it alarmed Catholics both inside and outside of France. François Viète • Philip II of Spain rather fancied his own daughter as successor to Henry III (who, by the way, was flamboyantly gay and unlikely to produce a lawful heir) rather than Henry of Navarre. Philip exchanged many letters with members of the French court in support of his daughter, even after Henry of Navarre assumed the throne as Henry IV. François Viète • These letters, written in code, were given to Viète to decode. He was so successful at this that Philip denounced him for being in league with the Devil. François Viète • During a period of exile from Henry III’s court (this was a very unsettled time in French history) he found the time to write several treatises that are collectively known as The Analytic Art, in which he effectively reformulated the study of algebra by replacing the search for solutions with a detailed study of the structure of equations. François Viète • Viète used upper case vowels (A, E, I, O, U, Y) to represent unknowns and upper case consonants to represent given constants. His symbolism was not complete, in the sense that he still used words to indicate powers – A2 is A quadratum, B3 would be B cubus, and C4 is C quadrato‐quadratum. He did at times use abbreviations such as A quad or C quad‐ quad. His rules for combining powers had to be given verbally. François Viète • Our equation , in Viète’s symbolism, would be: • B in A Quadratum, + D plano in A, aequari Z solido. • Here, he uses B, D and Z as known (but unspecified) numbers, and A as the unknown. The word “in” represents multiplication. The “+” sign was used for addition, as was “‐“ for subtraction. There was no “=” but instead some proper conjugation of the Latin verb aequare. François Viète • The words plano and solido demonstrate that Viète was strongly influenced by Greek concepts, since they are there to guarantee that the Z has “cubic” units, and the D has “square” units (resulting in “cubic” units when multiplied by A), thus guaranteeing that quantities of the same kind (cubic) are being added. Viète • On the other hand, he accepted larger powers in equations; he even solved a whopper of a 45th degree equation posed by Adriaan van Roomen. • Viète’s symbolism was to be further refined and superseded by that of René Descartes, who only a few years later gave us what amounts to our modern system of algebraic symbolism. Viète • Provided an approximation of correct to 10 decimals by using Archimedes’ method. • Wrote what seems to be the first infinite product by noting that Viète • What was his most important legacy? • Searching for Analysis • Systematizing algebra – “formulas, rather than rules.” “Focus on the procedures of the solution rather than the solution itself.” • “Replacing the search for solutions to equations by the detailed study of the structure of these equations.” Some Astronomy Nicolaus Copernicus • Mikołaj Kopernik, 19 February 1473 –24 May 1543 • Contributed to mathematics, medicine, astronomy, law, economics.