Wednesday, 10 June 2026

On This Day in Math - June 10

  



Mathematics is one of the essential emanations of the human spirit,
a thing to be valued in and for itself, like art or poetry.
~Oswald Veblen


The 161st day of the year, Every number greater than 161 is the sum of distinct primes of the form 6n - 1.  *Prime Curios (which numbers less than 161 are also the sum of distinct primes of the form 6n-1? or which are not?)

and for the gamblers out there, There are 161 ways to bet on a roulette wheel.
161 is not only a palindrome, when is rotated 180o it gives a palindromic prime, (191) (Such  reversible numbers, or words, which form a different number, or word, are called "ambigrams".)

161 is the sum of five consecutive prime numbers: 23 + 29 + 31 + 37 + 41 = 161



EVENTS

 1742 You will probably remember from your grade school education that George Washington spent several of his youthful years as a professional surveyor. But how much mathematics did he know and how did he use it as a surveyor? Thanks to two “cyphering books” (sometimes referred to as copybooks) he compiled as a teenager, we are able to show what he learned of trigonometry and surveying. The combined use of these subjects is perplexing to the modern reader, so we shall illustrate and explain the methods he used. Finally, in contrast to what one would expect, we will argue that he did not use trigonometry in surveying.

At age ten, Washington owned a copy of the thirteenth edition (1727) of  "The Young Man’s Companion; or, Arithmetic Made Easy", by William Mather. It is signed at the top of the title page: “George Washington” and the date “1742” is written to the right of the subtitle.

It is possible that Austin (his brother), hearing from his father of Washington’s growing interest in mathematics, brought the Mather book to him when he returned to Virginia on 10 June 1742.  We regard 1742 as the true beginning of Washington’s mathematical education.

The authors bring up the word decuple, which they say they had not heard, nor had I before reading their article.  It is clear from the suspect source of it appearing in young Washington's cyphering book; William Hawney, The Compleat Measurer: or, the Whole Art of Measuring  (1721).  

Left Washington's cypherbook
Right Hawney's Arithmetic


Checking on Google Ngram viewer, I found that after a great reduction in use around the time of Washington's early math instruction, it still seems to be used in education of four to eight year-olds: "Numbers close to a decuple , for instance , can be identified by using that decuple as a referent , e.g. 64 = 60 + 4 ; 37 40-3 . "

In a footnote, the authors expressed that it was very uncommon at this time for a cypherbook to deal with decimal fractions.  They said that Washington's was the earliest they had ever heard. A leader of his nation in one more way.

*George Washington's Use of Trigonometry and Logarithms, Joel S Silverberg, Fred Rickey,Thomas E. Dexter

A survey by Washington



Benjamin West *Wik

1752 This is the most common date given, where one is supplied, for the supposed Electrical kite experiment by Benjamin Franklin. The event is poorly documented. Franklin seems never to have written about it, and the only record seems to come from the pen of Joseph Priestly some fifteen years later who was told about it by Ben. Many now think the entire event never took place.

The standard account of Franklin's experiment was disputed following an investigation and experiments based on contemporaneous records by science historian Tom Tucker, the results of which were published in 2003. According to Tucker, Franklin never performed the experiment, and the kite as described is incapable of performing its alleged role.

Further doubt about the standard account has been cast by an investigation by the television series MythBusters. The team found evidence that Franklin would have received a fatal current through his heart had the event actually occurred. Nevertheless, they confirmed that certain aspects of the experiment were feasible - specifically, the ability of a kite with sufficiently damp string to receive and send to the ground the electrical energy delivered by a lightning strike.

Despite this, mainstream historians still support the view that the experiment was performed by Franklin *Wik

1827 William Rowan Hamilton, age 21, appointed astronomer royal at Dunsink Observatory and Andrews professor of astronomy at Trinity College, Ireland. This was a unique event in that he was still an undergraduate. *VFR


1854 The first known published mention of the Four Color Problem was printed in the Athenaeum on this date, appearing in the Miscellanea portion. The letter was signed with the initials F. G., which many supposed might have been one of the two Guthrie brothers involved in discovering the story and revealing it to DeMorgan, but others suspect it may have been Francis Galton, who had requested admission to the esteemed Athenaeum Club during this period. Certainly many of the members would have heard the story of the four colors problem from DeMorgan who had first circulated it to William R. Hamilton. (see October 23, 1852) *PB Notes (unknown)




1854, G.F. Bernhard Riemann proposed that space is curved in a lecture titled Über die Hypothesen welche der Geometrie zu Grunde liegen. He described the old-fashioned Euclidean plane geometry and solid geometry, respectively, as two-, and three-dimensional examples of what we now call Riemann spaces with zero curvature. Saying that the space is curved, rather than flat or Euclidean, is another way saying that the familiar properties of Euclidean geometry - such as the Pythagorean theorem - do not hold. He went on to suggest that all physical laws become simpler when expressed in higher dimensions. Einstein in 1915 used Rieman’s work in his theory of General Relativity which incorporated time as the fourth dimension.*TIS Weber recounted how with unusual emotion Gauss praised Riemann’s profundity on their way home. John Derbyshire in his Prime Obsession calls it "one of the top ten mathematical papers ever delivered anywhere."




1919 In a letter to Irving Langmuir, Ernest Rutherford writes, "I am a great believer in the simplicity of things and as you probably know I am inclined to hang on to broad & simple ideas like grim death until evidence is too strong for my tenacity." Nelson Ernest Rutherford *Quoted in Nathan Reingold and Ida H. Reingold, Science in America: A Documentary History 1900-1939 (1981), 354.


1924 Oswald Veblen describes his ideas for the Institute for Mathematical Research in a letter to Vernon Kellogg. The senior men would devote themselves “entirely to research, and to the guidance of the research of the younger men.” (History and philosophy of modern mathematics By William Aspray)




1977 The first Apple II computer was delivered. This was the first computer I ever used in a classroom.

Image : Apple II in a common 1977 configuration, with a 9" monochrome monitor, game paddles, and a Red Book-recommended Panasonic RQ-309DS cassette deck  *Wik

*Wik



In 2000, the Millennium Bridge - a footbridge across the River Thames - was opened by Queen Elizabeth. The radical new design was the work of architect Sir Norman Foster with sculptor Sir Anthony Caro and engineering support from Arup. It was the first new crossing of the River Thames in over 100. As the first few thousand people crossed the bridge, it developed an unexpected and potentially dangerous lateral "wobble". This caused people to unwittingly walk "in step", which increased the oscillation. The design had been adapted from a computer model typical for a car bridge, but which did not take into account the lateral forces associated with human walking. After structural damping was added to stop the oscillation, the bridge re-opened in 2002*TIS 






BIRTHS

940 Abu’l-Wafa (June 10, 940 AD, Buzhgan - July 1, 998 AD, Baghdad) He worked with a rusty compass.*VFR The professors cryptic remark about a "rusty compass" refers to Abu'l wafa's preference, when possible, to do his geometric constructions with a compass with a fixed opening.
Abu'l-Wafa is best known for the first use of the tan function and compiling tables of sines and tangents at 15' intervals. This work was done as part of an investigation into the orbit of the Moon, written down in Theories of the Moon. He also introduced the sec and cosec and studied the interrelations between the six trigonometric lines associated with an arc. He is also often credited as one of the likely originators of the spherical law of sines and established several trigonometric identities such as sin(a ± b) in their modern form, where the Ancient Greek mathematicians had expressed the equivalent identities in terms of chords.

\(\sin(\alpha \pm \beta) = \sin \alpha \cos \beta \pm \cos \alpha \sin \beta \)
"A text written by Abu'l-Wafa for practical use was A book on those geometric constructions which are necessary for a craftsman. This was written much later than his arithmetic text, certainly after 990. The book is in thirteen chapters and it considered the design and testing of drafting instruments, the construction of right angles, approximate angle trisections, constructions of parabolas, regular polygons and methods of inscribing them in and circumscribing them about given circles, inscribing of various polygons in given polygons, the division of figures such as plane polygons, and the division of spherical surfaces into regular spherical polygons.
Another interesting aspect of this particular work of Abu'l-Wafa's is that he tries where possible to solve his problems with ruler and compass constructions. When this is not possible he uses approximate methods. However, there are a whole collection of problems which he solves using a ruler and fixed compass, that is one where the angle between the legs of the compass is fixed. It is suggested in Dictionary of Scientific Biography that:-
Interest in these constructions was probably aroused by the fact that in practice they give more exact results than can be obtained by changing the compass opening.

 His trigonometric tables are accurate to 8 decimal places (converted to decimal notation) while Ptolemy's were only accurate to 3 places." *SAU

In 2015, Google celebrated his 1075th birthday with a Google Doodle, and included, "contributions to science include one of the first known introductions to negative numbers, and the development of the first wall quadrant, a tool used by astronomers to examine the sky."

It is interesting that during this period there were two types of arithmetic books written, those using Indian symbols and those of finger-reckoning type. Abu'l-Wafa's text is of this second type with no numerals; all the numbers are written in words and all calculations are performed mentally. It is now believed that mathematicians wrote for two differing types of readers. Abu'l-Wafa himself was an expert in the use of Indian numerals but these :-"... did not find application in business circles and among the population of the Eastern Caliphate for a long time."

Hence he wrote his text using finger-reckoning arithmetic since this was the system used for by the business community. *SAU *Wik *PB


1710 James Short (June 10, 1710, Edinburgh, Scot. -  June 14, 1768, London, Eng) British optician and astronomer who produced the first truly parabolic and elliptic (hence nearly distortionless) mirrors for reflecting telescopes.

 During his working life of over 35 years, Short made about 1,360 instruments - not only for customers in Britain but also for export: one is still preserved in Leningrad, another at Uppsala and several in America. Short was principal British collator and computer of the Transit of Venus observations made throughout the world on 6th June 1761. His instruments traveled on Endeavour with Captain Cook to observe the next Transit of Venus on 3rd June 1769, but Short died before this event took place.


1803 Henri-Philibert-Gaspard Darcy (June 10, 1803 – January 3, 1858) French hydraulic engineer who first derived the equation (now known as Darcy's law) that governs the laminar (nonturbulent) flow of fluids in homogeneous, porous media. In 1856, modern studies of groundwater began when Darcy was commissioned to develop a water-purification system for the city of Dijon, France. He constructed the first experimental apparatus to study the flow characteristics of water through the earth. From his experiments, he derived the Darcy's Law equation, describing the flow of water in nature, which is fundamental to understanding groundwater systems.




1861 Pierre(-Maurice-Marie) Duhem (10 June 1861 – 14 September 1916)French physicist, mathematician, and philosopher of science who emphasized a history of modern science based on evolutionary metaphysical concepts. He had a wide variety of mathematical interests from mechanics and physics to philosophy and the history of mathematics. Duhem studied magnetism following the work of Gibbs and Helmholtz and also worked on thermodynamics and hydrodynamics producing over 400 papers. He maintained that the role of theory in science is to systematize relationships rather than to interpret new phenomena.  *TIS




1887 Vladimir Ivanovich Smirnov (10 June 1887 – 11 February 1974) was a Russian mathematician who made significant contributions in both pure and applied mathematics, and also in the history of mathematics.
Smirnov worked on diverse areas of mathematics, such as complex functions and conjugate functions in Euclidean spaces. In the applied field his work includes the propagation of waves in elastic media with plane boundaries (with Sergei Sobolev) and the oscillations of elastic spheres.
Smirnov is also widely known among students for his five volume book A Course in Higher Mathematics (the first volume was written jointly with Jacob Tamarkin).*Wik



1904 John Semple (10 June 1904 in Belfast, Ireland - 23 October 1985 in London, England) studied at Queen's University Belfast and Cambridge. He held a post in Edinburgh for a year before becoming Professor of Pure Mathematics at Queen's College Belfast. He moved to King's College London where he spent the rest of his career. His most important work was in Algebraic geometry. *SAU


1932 Pierre Emile Jean Cartier (10 June 1932 in Sedan , Ardennes - ) is a French mathematician . His main interest is the algebraic geometry , presentation and category theory . 1957-1959 he worked at the Institute for Advanced Study . From 1961 he was a professor at the University of Strasbourg (then Faculté de Science). In 1971 he was appointed professor at the Institut des Hautes Études Scientifiques in Paris. He was also from 1974 Director of Research CNRS. In 1982 he became a professor at the Ecole Polytechnique and 1988 at the ENS. Pierre Cartier led the Cartier operator and is the namesake of the Cartier divisor . *Wik



1987 James Alexander Maynard FRS (born 10 June 1987) is an English mathematician working in analytic number theory and in particular the theory of prime numbers. In 2017, he was appointed Research Professor at Oxford. Maynard is a fellow of St John's College, Oxford. He was awarded the Fields Medal in 2022 and the New Horizons in Mathematics Prize in 2023.
In August 2014, Maynard (independently of Ford, Green, Konyagin and Tao) resolved a longstanding conjecture of Erdős on large gaps between primes, and received the largest Erdős prize ($10,000) ever offered.

In 2014, he was awarded the SASTRA Ramanujan Prize. In 2015, he was awarded a Whitehead Prize and in 2016 an EMS Prize.

In 2016, he showed that, for any given decimal digit, there are infinitely many prime numbers that do not have that digit in their decimal expansion.

In 2019, together with Dimitris Koukoulopoulos, he proved the Duffin–Schaeffer conjecture.
Maynard was awarded the Fields Medal 2022 for "contributions to analytic number theory, which have led to major advances in the understanding of the structure of prime numbers and in Diophantine approximation".
Maynard was elected a Fellow of the Royal Society (FRS) in 2023.




DEATHS


1836 Andre-Marie Ampere(20 January 1775 – 10 June 1836)French mathematician and physicist who founded and named the science of electrodynamics, now known as electromagnetism. His interests included mathematics, metaphysics, physics and chemistry. In mathematics he worked on partial differential equations. Ampère made significant contributions to chemistry. In 1811 he suggested that an anhydrous acid prepared two years earlier was a compound of hydrogen with an unknown element, analogous to chlorine, for which he suggested the name fluorine. He produced a classification of elements in 1816. Ampère also worked on the wave theory of light. By the early 1820's, Ampère was working on a combined theory of electricity and magnetism, after hearing about Oersted's experiments.TIS It is said that Ampere was capable of intense concentration leading to absent-mindedness. Once walking in Paris he had an insight and pulled a piece of chalk out of his pocket and finding the back of a cab he began to cover the back of the cab with equations, and was then shocked to see his solution begin to pull away and disappear down the street.





1903 (Antonio) Luigi (Gaudenzio Giuseppe) Cremona ( Pavia , 7 December 1830 - Rome , 10 June 1903 ) was an Italian mathematician who was an originator of graphical statics (the use of graphical methods to study forces in equilibrium) and work in projective geometry. Cremona's work in statics is of great importance and he gave, in a clearer form, some theorems due to Maxwell. In a paper of 1872 Cremona took an idea of Maxwell's on forces in frame structures that had appeared in an engineering journal in 1867 and interpreted Maxwell's notion of reciprocal figures as duality in projective 3-space. These reciprocal figures, for example, have three forces in equilibrium in one figure represented by a triangle while in the reciprocal figure they are represented by three concurrent lines.*TIS





1948 Philippa Garrett Fawcett (4 April 1868 - 10 June 1948)
Fawcett's performance in the Trinity Intercollege Examination which she sat after two years at Cambridge was outstanding and it was clear that she would excel in the Tripos Examinations of 1890. At this time only the men were ranked in the Tripos Examination but women who took the examination were made aware of their place by being told they were placed between the nth and (n+1)st man or equal to the nth man. Expectations were high that Fawcett would perform well and her mother wrote in a letter to a friend):-

I am going to Cambridge tomorrow week and shall have my last sight of [Philippa] till after the exam. I have made up my mind not to be too anxious about it. There are a great many better things in the world than beating other people in examinations.

However, beat other people is exactly what Fawcett did in the twelve three hour examination papers. The Senior Moderator of the Mathematical Tripos Examinations of 1890 was Walter Rouse Ball and it was his duty to read the women's list after the men's ranked list had been read. When Rouse Ball came to read the women's list he read out first:-
Miss Philippa Garrett Fawcett - above the Senior Wrangler.
Fawcett had become the first woman at Cambridge to come top in the Mathematical Tripos Examinations. A description of the event is recorded in the North Hall Diary of Newnham College:-
The great event of the year was Philippa Garrett Fawcet's achievement in the Mathematical Tripos. For the first time a woman has been placed above the Senior Wrangler. The excitement in the Senate House when the lists were read was unparalleled. The deafening cheers of the throng of undergraduates redoubled as Miss Fawcett left the Senate House by the side of the Principal. On her arrival at the College she was enthusiastically greeted by a crowd of fellow-students, and carried in triumph into Clough Hall. Flowers, letters, and telegrams poured in upon her throughout the day. The College was profusely decorated with flags. In the evening the whole College dined in Clough Hall. After dinner toasts were proposed: the healths drunk were those of the Principal, Miss Fawcett, her Coach (Mr Hobson) and Senior and Junior Optimes. At 9.30 p.m. the College gardens were illuminated, and a bonfire was lighted on the hockey-ground, round which Miss Fawcett was three times carried amid shouts of triumph and strains of "For she's a jolly good fellow." *SAU

Following Fawcett's great achievement in the Mathematical Tripos, she won a scholarship at Cambridge through which she conducted research in Fluid Dynamics. Her published papers include "Note on the Motion of Solids in a Liquid".

She went on to be a College Lecturer in Mathematics at Newnham College, Cambridge a position she held for 10 years. In this capacity, her teaching abilities received considerable praise. One student wrote:
“ What I remember most vividly of Miss Fawcett's coaching was her concentration, speed, and infectious delight in what she was teaching. She was ruthless towards mistakes and carelessness... My deepest debt to her is a sense of the unity of all truth, from the smallest detail to the highest that we know. ”
Fawcett left Cambridge in 1902, when she was appointed as a lecturer to train mathematics teachers at the Normal School, Johannesburg, South Africa. Here, she remained until 1905, setting up schools in South Africa. She then returned to England to take a position in the administration of education for London County Council. Here, she attained the highest LCC rank ever for a woman, in her work developing secondary schools.
Philippa Fawcett maintained strong links with Newnham College throughout her life. The Fawcett building (1938) was named in recognition of her contribution to Newnham, and that of her family. She died on 10 June 1948, two months after her 80th birthday, just one month after the Grace that allowed women to be awarded the Cambridge BA degree received royal assent, and fifty eight years after coming above the `Senior Wrangler'. *Wik

Philippa on Newham Field Hockey team




1974 Jaroslav Hájek (4 Feb 1926 in Podebrady, Bohemia (now Czech Republic) - 10 June 1974 in Prague, Czechoslovakia) He was among the pioneers of unequal probability sampling. The name "Hájek predictor" now labels his contributions to the use of auxiliary data in estimating population means. In 1967 Hájek published (jointly with Z Sidak) Theory of rank tests but it was a work which had in fact been written four years before in 1963. Their methods use three lemmas of Le Cam in order to treat rank statistics under local alternatives and they established the efficiency of rank tests. *SAU




1992 Morris Kline (May 1, 1908 – June 10, 1992) was a Professor of Mathematics, a writer on the history, philosophy, and teaching of mathematics, and also a popularizer of mathematical subjects.
Kline grew up in Brooklyn and in Jamaica, Queens. After graduating from Boys High School in Brooklyn, he studied mathematics at New York University, earning a bachelor's degree in 1930, a master's degree in 1932, and a doctorate in 1936. He continued at NYU as an instructor until 1942.
During World War II, Kline was posted to the Signal Corps (United States Army) stationed at Belmar, New Jersey. Designated a physicist, he worked in the engineering lab where radar was developed. After the war he continued investigating electromagnetism, and from 1946 to 1966 was director of the division for electromagnetic research at the Courant Institute of Mathematical Sciences.
Kline resumed his mathematical teaching at NYU, becoming a full professor in 1952. He taught at New York University until 1975, and wrote many papers and more than a dozen books on various aspects of mathematics and particularly mathematics teaching. He repeatedly stressed the need to teach the applications and usefulness of mathematics rather than expecting students to enjoy it for its own sake. Similarly, he urged that mathematical research concentrate on solving problems posed in other fields rather than building structures of interest only to other mathematicians. *Wik




2007 Hans-Jürgen Hoehnke (* 27 October 1925 in Danzig ; † 10 June 2007 ) was a German mathematician who dealt with algebra.

After graduating from high school in 1943 at the Ordensburg Sonthofen, Hoehnke attended the Air Force School and from 1946 studied mathematics at Martin Luther University Halle , where he received his doctorate in 1952 under Heinrich Brandt (on the transformation properties of nonions). Prior to this, after completing his studies in 1949, he worked as a mathematician at the Buna Chemical Works and in the electrical industry in Vacha an der Rhön. As a teenager, he was a radio enthusiast. After receiving his doctorate, he became Brandt's assistant in Halle. From 1956 until his retirement in 1990, he worked at the Mathematical Institute of the Academy of Sciences of the GDR in Berlin ( Central Institute for Mathematics and Mechanics , ZIMM). In 1965, he earned his habilitation at Humboldt University of Berlin (on the theory of groupoids).

At the Mathematical Institute, he was an outsider as a representative of abstract algebra because his research area was considered not systemically relevant, and more emphasis was placed on applied research. Hoehnke's resistance to this classification led to political distrust of him. Upon returning from a trip abroad, he learned that he was no longer head of the Institute for Pure Mathematics. [ 1 ] He also never received the title of professor, despite the international recognition of his work. This setback also prompted him to leave the Academy Institute after the fall of the Berlin Wall in 1990, before his 65th birthday. In 1998, he was recognized as a victim of political persecution and rehabilitated as the acting director of the Institute for Pure Mathematics. 

He organized a series of conferences, including workshops on general algebra and related fields (later continued as the workshop on general algebra ), and a conference for young algebraists in Potsdam, where he maintained close contact with a group of algebraists at the Pedagogical University. He had many international contacts and was co-editor of Mathematica Japonica (Scientiae Mathematicae Japonicae) and Semigroup Forum.

Initially, he focused on constructive methods in algebra, later on general algebra, semigroups, groupoids, clones, homological algebra, axiomatic theory of radicals, automata theory, and algebraic questions in logic. Hoehnke categories (dht-symmetric categories) and Hoehnke radicals are named after him. *Wik







Credits
*CHM=Computer History Museum
*FFF=Kane, Famous First Facts
*NSEC= NASA Solar Eclipse Calendar
*RMAT= The Renaissance Mathematicus, Thony Christie
*SAU=St Andrews Univ. Math History
*TIA = Today in Astronomy
*TIS= Today in Science History
*VFR = V Frederick Rickey, USMA
*Wik = Wikipedia
*WM = Women of Mathematics, Grinstein & Campbell

Tuesday, 9 June 2026

Regular Polygons Inscribed in a Similar Regular Polygon

  


A long time back, I wrote about some geometric options for a problem I had found on Greg Ross' Futility Closet. Shortly afterward I got a note from a blogger at "Five Triangles" who mentioned he had posted a very similar problem (above) about a year earlier.

What I especially enjoyed about his presentation of the problem was the obvious invitation to generalize the idea to regular polygons of more sides.
Each of the figures is simplified by the visual approach of rotating the inner polygon until it has its vertices at the midpoints of the sides of the larger. From there it is almost trivial that for the triangles, the smaller is 1/4 the larger (the logo of the five-triangles web site shows this clearly), and the smaller square is 1/2 the larger.(top image)

When you go to five sides the quick visual solutions disappear, but a generalization should offer itself to a clever trig student. If we assume the sides of the larger n-gon are each of unit length, then the area of the two polygons should be in the same ratio as the square of the side of the smaller polygon..... ( some were confused by this, the area of two similar polygons are in the ratio of the square of their corresponding side, but since we et the larger at one unit, its square is 1 square unit, and so the ratio of the two area is the square of the inner edge length over one.)....and a clever trig student looking at all those triangles (such as the blue FGB) formed between the two polygons should know a quick rule for finding the square of the side lengths of the inner polygon.... the beautiful extension of the Pythagorean theorem they know as the law of cosines.


Since each leg on the outside of the triangle is \(\frac{1}{2}\) unit, and the angle is \(\frac{\pi(n-2)}{n}\) it should be easy to determine that the square of the sides of the inner polygon is \(\frac {1}{2})^2 + (\frac {1}{2})^2 - 2 *(\frac {1}{2}*\frac {1}{2} * \cos(\frac{\pi(n-2)}{n})\) Or more simply, \(\frac {1}{2}(1-\cos(\frac{\pi(n-2)}{n}))\)
For values from n= 3 to 12 I came up with the following with the support of Wolframalpha:


Only the triangle, square, and hexagons produced rational roots, in convenient consecutive quarters for easy remembering.  The decimal approximations clearly support the intuitive idea that the limit should approach one as n grows larger without bound. By the time you get to the hectogon, the ratio is ,9990.  Fans of the "golden ratio will appreciate its appearance in the pentagon even if slightly camouflaged.

N      Ratio
3 ..... 0.25
4 ..... 0.5
5 ..... 0.654508
6 ..... 0.75
7 ..... 0.811745
8 ..... 0.853553
9 ..... 0.883022 
10 .... 0.904508
11 .... 0.920627
12 .... 0.933013
 
An interesting exploration, I think, for good trig students to explore.  Enjoy
 

On This Day in Math - June 9

  

The Boat House, Paducah, Ky


I've been giving this lecture to first-year classes
for over twenty-five years. 
You'd think they would begin to understand it by now.
~ J E Littlewood




The 160th day of the year; 160 is the smallest number which is sum of cubes of 3 distinct primes, the first three. (23+33+53) *Prime Curios (It is also the sum of the first power of the first 11 primes )

160! - 159! + 158! - ... -3! + 2! - 1! is prime.

160 is also the sum of two non-zero squares (122 + 42) and like all such numbers, you can show that 1602n+1 will also be the sum of two non-zero squares.

160 is the longest edge of the integer Heronian tetrahedron with smallest possible surface area and volume.  Its edges are 25, 39, 56, 120, 153, and 160; for a total surface area of 6384, and volume 8064.

Another Heronian triangle






160 is the largest year day (and second largest known) for which the alternating factorial sequence is prime: 160!- 159! + 158! - 157! .... + 2! - 1!. The alternating factorial 5! - 4! + 3! - 2! + 1! = 121. The alternating factorial sequence is prime for n= 3 through 8 (5, 19, 101, 619, 4421, 35899). In spite of this run of consecutive primes, John D Cook checked and found only 15 n values for which the alternating factorial starting with n is prime (There are now at least 17 known primes). 14 are year days, the largest being 160. 


More info on these here 
Find more math facts for each year day here


EVENTS

1750 Euler finally was able to prove the pentagonal theorem on June 9, 1750, in a letter to Goldbach. His proof is algebraic. The proof was first published in 1760, and Euler gives more details about points which were vague in his letter to Goldbach.
Euler had mentioned the theorem many times in the years following his first correspondence with Daniel Bernoulli (January 28,1741), in letters to Niklaus Bernoulli, Christian Goldbach, d’Alembert, and others, and in the first publication of 1751. (This paper was written on April 6, 1741 and had no proof. Euler wrote so many papers that the publishers fell dramatically behind; they were publishing new papers many years after his death.) A typical entry, from a letter to Goldbach, reads “If these factors \((1 − n)(1 − n^2)(1 − n^3) etc. are multiplied out onto infinity, the following series \(1 − n − n^2 + n^5 + n^7− etc is produced. I have however not yet found a method by which I could prove the identity of these two expressions. The Hr. Prof. Niklaus Bernoulli has also been able to prove nothing beyond induction.” Here the word “induction” means “by experiment” rather than “a proof by induction”. *Dick Koch, The Pentagonal Theorem and All That




1795 a provisional meter bar was constructed in brass by Lenoir. On 1 Aug 1793, the metre had been defined to be 1/10 000 000 of the northern quadrant of the Paris meridian (5 132 430 toises of Paris, from the north pole to the equator). On 7 Apr 1795, the first legal definition of the metre was made by the French National Assembly. A second measure was made along the Dunkirk-Barcelona axis (5 130 740 toises of Paris).
Closeup of National Prototype Metre Bar No. 27, made in 1889 by the International Bureau of Weights and Measures (BIPM) and given to the United States, which served as the standard for defining all units of length in the US from 1893 to 1960.  (the distance between two lines on a standard bar of an alloy of platinum with 10% iridium, measured at the melting point of ice) *Wik






1798 Napoleon’s fleet of 500 ships arrived in Malta, and three days later they captured the place. Monge started fifteen elementary schools and one high school there.*VFR

1905  Albert Einstein published his analysis of Planck's quantum theory and its application to light. His article appeared in Annalen der Physik. Though no experimental work was involved, it was for these insights that Einstein earned his Nobel Prize. *TIS
 Einstein quickly realized that Planck’s hypothesis about the quantization of radiant energy could also explain the photoelectric effect. Einstein used Planck's concept of the quantization of energy to explain the photoelectric effect, the ejection of electrons from certain metals when exposed to light. Einstein postulated the existence of what today we call photons, particles of light with a particular energy, E = hν.





1934 First Donald Duck Cartoon. Amazingly, the "Donald in Mathland" videos that were popular in the eighties in middle schools are still for sell.


BIRTHS

1669 Leonty Filippovich Magnitsky (9 June 1669 in Ostashkov, Russia - 30 October 1739 in Moscow, Russia) Peter the Great, Tsar of Russia, founded the School of Mathematics and Navigation in Moscow in 1701. Russia was a major power at this time but had no access to the sea. Peter decided that he would push north to try to dislodge the Swedes who controlled the Baltic coast and war had begun on this front in 1700. The many reforms, including the start of secular education, which Peter introduced to modernize Russia aimed to ensure victory in his wars for access to the seas. The declaration setting up the Moscow School was dated 14 January 1701, but formal classes did not begin immediately. There was a delay since facilities were not properly in place to allow teaching to begin. Peter the Great then appointed Magnitskii to the School on 2 February
In February, Magnitskii was appointed to the school and simultaneously ordered to compile a book "in the Slavonic dialect, selected from arithmetic, geometry and navigation." The 'Arithmetic' was therefore specifically commissioned to be the textbook of the Moscow School. Little is known about the classes in the school while the book was being prepared. It was sent to the publisher on 2 November 1702, and appeared bearing the date 11 January 1703. With its appearance the success of the school was assured.
The 'Arithmetic' was the first mathematics textbook published in Russia by a Russian which was not a translation or adaptation of a foreign textbook. It was a textbook for the courses which Magnitskii himself taught at the school, essentially a published version of his lecture notes. It was in effect an encyclopaedia of the mathematical sciences of its day, based strongly on applications in navigational astronomy, geodesy and navigation. It used the methods of algebra, geometry, and trigonometry. The 'Arithmetic',remained the basic Russian mathematics textbook for 50 years. *SAU




1812 Johann Gottfried Galle (9 June 1812 – 10 July 1910) German astronomer who on 23 Sep 1846, was the first to observe the planet Neptune, whose existence had been predicted in the calculations of Leverrier. Leverrier had written to Galle asking him to search for the 'new planet' at a predicted location. Galle was then a member of the staff of the Berlin Observatory and had discovered three comets. In 1838, while assistant to Johann Franz Encke, Galle discovered the dark, inner C ring of Saturn at the time of the maxium ring opening. In 1851, he became professor of astronomy at Breslau and director of the observatory there. In 1872, he proposed the use of asteroids rather than regular planets for determinations of the solar parallax, a suggestion which was successful in an international campaign (1888-89).




1885 John Edensor Littlewood born. (9 June 1885 – 6 September 1977) Littlewood’s Miscellany (1986) is a delightful little book, for it shows a mathematician having fun.*VFR
He collaborated for many years with G. H. Hardy. Together they devised the first Hardy–Littlewood conjecture, a strong form of the twin prime conjecture, and the second Hardy–Littlewood conjecture.
In a 1947 lecture, the Danish mathematician Harald Bohr said, "To illustrate to what extent Hardy and Littlewood in the course of the years came to be considered as the leaders of recent English mathematical research, I may report what an excellent colleague once jokingly said: 'Nowadays, there are only three really great English mathematicians: Hardy, Littlewood, and Hardy–Littlewood.'"
There is a story (related in the Miscellany) that at a conference Littlewood met a German mathematician who said he was most interested to discover that Littlewood really existed, as he had always assumed that Littlewood was a name used by Hardy for lesser work which he did not want to put out under his own name; Littlewood apparently roared with laughter. There are versions of this story involving both Norbert Wiener and Edmund Landau, who, it is claimed, "so doubted the existence of Littlewood that he made a special trip to Great Britain to see the man with his own eyes"*Wik




1906 Albert Cyril Offord FRS FRSE (9 June 1906 – 4 June 2000) was a British mathematician. He was the first professor of mathematics at the London School of Economics.
 He was educated at Hackney Downs Grammar School. He then studied Mathematics at University College, London. He then went to St John's College, Cambridge as a postgraduate, working with Prof John Edensor Littlewood.

He received two Ph.D.s in mathematics: the first from the University of London (under Bosanquet) in 1932, the second from Cambridge (under Hardy) in 1936.

In 1940 he left Cambridge to lecture at University College, Bangor. In 1942 he moved to King's College, Newcastle-upon-Tyne (later being named the University of Newcastle). He was created Professor of Mathematics in 1945.

In 1946 he was elected a Fellow of the Royal Society of Edinburgh. His proposers were Sir Edmund Whittaker, John William Heslop-Harrison, Alexander Aitken and Alfred Dennis Hobson. He was elected a Fellow of the Royal Society of London in 1952.

In 1948 he left Newcastle to become Professor of Mathematics at Birkbeck College in London replacing Prof Dienes. He left in 1966 to take up a new chair at London School of Economics. He retired in 1973 then becoming a senior research fellow at Imperial College, London.

He died in Oxford on 4 June 2000.



1909  Wade Ellis (June 9, 1909 – November 20, 1989) was an American mathematician and educator. He taught at Fort Valley State University in Georgia and Fisk University in Nashville, Tennessee and earned his Ph.D. in mathematics from the University of Michigan in 1944. He carried out classified research on radar antennas at the MIT Lincoln Laboratory and taught at Boston University and Oberlin College, where he became Full Professor in 1953. The same year, he was elected to the Board of Governors of the Mathematical Association of America.

Ellis promoted mathematical education and was decorated for his efforts in 1966 by the government of Peru. He returned to the University of Michigan in 1967 as Associate Dean of the Graduate School and Professor of Mathematics until his retirement in 1977, when he was named professor emeritus. Afterwards, he served in various administrative positions including vice chancellor of academic affairs at University of Maryland Eastern Shore and interim president of Marygrove College in Detroit.




1913 Muriel Kennett Wales (9 Jun 1913 – 8 August 2009) was an Irish-Canadian mathematician, and is believed to have been the first Irish-born woman to earn a PhD in pure mathematics.  [Some hold out for  Siobhan O’Shea (married name Vernon, born and reared in Macroom, Cork), who in 1964 received her PhD from University College Cork - – National University of Ireland, Cork, for a thesis consisting of previously published papers in analysis  ].

Muriel Wales  was first educated at the University of British Columbia (BA 1934, MA 1937 with the thesis Determination of Bases for Certain Quartic Number Fields). In 1941 she was awarded the PhD from the University of Toronto for the dissertation Theory Of Algebraic Functions Based On The Use Of Cycles under Samuel Beatty  (himself the first person to receive a PhD in mathematics in Canada, in 1915).

She spent most of the 1940s working in atomic energy, in Toronto and Montreal, but by 1949 had retired back to Vancouver where she worked in her step-father's shipping company.*Wik





1960  Carlo W. J. Beenakker (born June 9, 1960) is a professor at Leiden University and leader of the university's mesoscopic physics group, established in 1992. In 1997, he was awarded the Spinoza Prize, the "Dutch Nobel prize". *Wik
In 1993, he shared the Royal/Shell prize for "the discovery and explanation of quantum effects in the electrical conduction in mesoscopic systems". He was elected a member of the Royal Holland Society of Sciences and Humanities in 2001, and the Royal Netherlands Academy of Arts and Sciences in 2002. He was awarded one of the Netherlands' most prestigious science awards, the Spinozapremie, in 1999. In 2006 he was honored with the AkzoNobel Science Award "for his pioneering work in the field of nanoscience". He was granted an honorary doctorate from the Bogolyubov Institute for Theoretical Physics of the National Academy of Sciences of Ukraine. Beenakker is a Fellow of the American Association for the Advancement of Science and of the American Physical Society and a Knight of the Order of the Netherlands Lion. *Wik




1983 June E Huh ( June 9, 1983,  ) is an American mathematician who is currently a professor at Princeton University. Previously, he was a professor at Stanford University. He was awarded the Fields Medal and a MacArthur Fellowship in 2022. He has been noted for the linkages that he has found between algebraic geometry and combinatorics.
Huh was born in Stanford, California while his parents were completing graduate school at Stanford University. He was raised in South Korea, where his family returned when he was approximately two years old. His father was a professor of statistics at Korea University, while his mother was a professor of Russian language at Seoul National University. Poor scores on elementary school tests convinced him that he lacked the innate aptitude to excel in mathematics. He later dropped out of high school to focus on writing poetry after becoming bored and exhausted by the constant routine of relentless studying. Huh has been described as a late bloomer, both in terms of his career phenomena and with regards to his academic and professional development. Huh matriculated at Seoul National University in 2002, but found himself initially unsettled and suffering from depression. He pinned his initial career aspirations on becoming a science journalist and decided to major in physics and astronomy, but compiled a poor attendance record and had to repeat several courses that he initially failed at.
Early in his studies he was mentored by Japanese award-winning mathematician Heisuke Hironaka, who went to Seoul National University as a visiting professor. Having failed several courses, Huh took an algebraic geometry course under Hironaka in his sixth year which focused on singularity theory and was based on Hironaka's current research rather than established teaching material. Huh credited the course with sparking his interest in research-level math. Huh then proceeded to complete a master's degree at Seoul National University, while frequently travelling to Japan with Hironaka and acting as his personal assistant.[6] Due to his poor academic record as an undergraduate, Huh was rejected from all but one of the American universities that he applied to. He started his Ph.D. studies at the University of Illinois Urbana-Champaign in 2009, before transferring to the University of Michigan in 2011. He graduated in 2014 with a thesis written under the direction of Mircea Mustață at the age of 31. He was awarded the Sumner Byron Myers Prize for his PhD thesis.
Huh is married to Kim Nayoung, whom he met during his studies while attending Seoul National University. Kim is a graduate of Seoul National University where she earned her doctorate in mathematics. The couple has two sons.






DEATHS


1751 John Machin
 (bapt. 1686?—June 9, 1751) was an English mathematician and astronomer best known for the formulas he invented for calculating π.*VFR
He was a professor of astronomy at Gresham College, London, and is best known for developing a quickly converging series for Pi in 1706 and using it to compute Pi to 100 decimal places.
Machin's formula is:
\frac{\pi}{4} = 4 \cot^{-1}5 - \cot^{-1}239
The benefit of the new formula, a variation on the Gregory/Leibniz series (Pi/4 = arctan 1), was that it had a significantly increased rate of convergence, which made it a much more practical method of calculation.
To compute Pi to 100 decimal places, he combined his formula with the Taylor series expansion for the inverse tangent. (Brook Taylor was Machin's contemporary in Cambridge University.) Machin's formula remained the primary tool of Pi-hunters for centuries (well into the computer era).*Wik "This formula of John Machin (1680–1751) was publicized by William Jones in his 1706 Synopsis palmariorum matheseos. Variations of it remained the standard method for calculating τ/2 (pi) until the 1970s, when better methods due to Ramanujan came to light." *Theorem of the Day




1786 William George Horner (9 June 1786 – 22 September 1837) was a British mathematician. Proficient in classics and mathematics, he was a schoolmaster, headmaster and schoolkeeper who wrote extensively on functional equations, number theory and approximation theory, but also on optics. His contribution to approximation theory is honoured in the designation Horner's method, in particular respect of a paper in Philosophical Transactions of the Royal Society of London for 1819. The modern invention of the zoetrope, under the name Daedaleum in 1834, has been attributed to him.

Horner died comparatively young, before the establishment of specialist, regular scientific periodicals. So, the way others have written about him has tended to diverge, sometimes markedly, from his own prolific, if dispersed, record of publications and the contemporary reception of them.
Horner's name first appears in the list of solvers of the mathematical problems in The Ladies' Diary: or, Woman's Almanack for 1811, continuing in the successive annual issues until that for 1817. Up until the issue for 1816, he is listed as solving all but a few of the fifteen problems each year; several of his answers were printed, along with two problems he proposed. He also contributed to other departments of the Diary, not without distinction, reflecting the fact that he was known to be an all-rounder, competent in the classics as well as in mathematics. Horner was ever vigilant in his reading, as shown by his characteristic return to the Diary for 1821 in a discussion of the Prize Problem, where he reminds readers of an item in (Thomson's) Annals of Philosophy for 1817; several other problems in the Diary that year were solved by his youngest brother, Joseph.

Although Horner's article on the Dædalum (zoetrope) appeared in Philosophical Magazine only in January, 1834, he had published on Camera lucida as early as August, 1815.
In mathematics and computer science, Horner's method (or Horner's scheme) is an algorithm for polynomial evaluation. Although named after William George Horner, this method is much older, as it has been attributed to Joseph-Louis Lagrange by Horner himself, and can be traced back many hundreds of years to Chinese and Persian mathematicians. After the introduction of computers, this algorithm became fundamental for computing efficiently with polynomials.







1818 Joel E. Hendricks, (March 10, 1818 - June 9, 1893) a noted mathematician, was born in Bucks County, Pennsylvania, March 10, 1818. He early developed a love of mathematics and began to teach school at nineteen years of age. He chanced to procure Moore's Navigation and Ostrander's Astronomy and, without instruction, soon became able to work in trigonometry and calculate solar and lunar eclipses. He took up algebra while teaching and soon became master of that science without instruction. He taught mathematics two years in Neville Academy, Ohio, and then occupied a position on a Government survey in Colorado in 1861. In 1864 he located in Des Moines, Iowa and pursued his mathematical studies. In 1874 he began the publication of the Analyst, a journal of pure and applied mathematics and soon won a reputation in Europe among eminent scholars as one of the most advanced mathematicians of the day. His Analyst was taken by the colleges and universities of Europe and found a place in the best foreign libraries. His name became famous among all mathematical experts of the world. Among his correspondents were Benjamin Silliman, John W. Draper and James D. Dana; while his journal was authority at Yale and Johns Hopkins Universities. For ten years, up to 1884, this world-famous Analyst was published at Des Moines by Dr. Joel E. Hendricks. Up to the time it was discontinued, no journal of mathematics had been published so long in America." [Hendricks made arrangements to have it taken over by new management, and it was continued from March 1884 as the Annals of Mathematics.]

It is one of the remarkable events of the Nineteenth Century that a self-educated man should, by his own genius and industry, without instruction, reach such an exalted place among the world's great scholars. Dr. Hendricks died in Des Moines on the 9th of June, 1893. *History of Iowa From the Earliest Times to the Beginning of the Twentieth Century/Volume 4 by Benjamin F. Gue
A more complete mathematical biography of Mr. Hendricks can be found in The American Mathematical Monthly, Vol 1, #3, 1894.





1847 John Hailstone (13 Dec, 1759– 9 June, 1847), English geologist, born near London, was placed at an early age under the care of a maternal uncle at York, and was sent to Beverley school in the East Riding. Samuel Hailstone was a younger brother. John went to Cambridge, entering first at Catharine Hall, and afterwards at Trinity College, and was second wrangler and second in the Smith Prize of his year (1782). He was second in both competitions to James Wood who became master of Saint Johns, and Dean of Ely. Hailstone was elected fellow of Trinity in 1784, and four years later became Woodwardian Professor of Geology, an office which he held for thirty years.
He went to Germany, and studied geology under Werner at Freiburg for about twelve months. On his return to Cambridge he devoted himself to the study and collection of geological specimens, but did not deliver any lectures. He published, however, in 1792, ‘A Plan of a course of lectures.’
He married, and retired to the vicarage of Trumpington, near Cambridge, in 1818, and worked zealously for the education of the poor of his parish. He devoted much attention to chemistry and mineralogy, as well as to his favourite science, and kept for many years a meteorological diary. He made additions to the Woodwardian Museum, and left manuscript journals of his travels at home and abroad, and much correspondence on geological subjects. He was elected to the Linnean Society in 1800, and to the Royal Society in 1801, and was one of the original members of the Geological Society. Hailstone contributed papers to the ‘Transactions of the Geological Society’ (1816, iii. 243–50), the ‘Transactions of the Cambridge Philosophical Society’ (1822, i. 453–8), and the British Association (Report, 1834, p. 569). He died at Trumpington in his eighty-eighth year. *Wik




1897 Alvan Graham Clark (July 10, 1832 – June 9, 1897) U.S. astronomer, one of an American family of telescope makers and astronomers who supplied unexcelled lenses to many observatories in the U.S. and Europe during the heyday of the refracting telescope. He began a deep interest in astronomy while still at school, then joined the family firm of Alvan Clark & Sons, makers of astronomical lenses. In 1861, testing a new lens, he looked through it at Sirius and observed faintly beside it, Sirius B, the twin star predicted by Friedrich Bessel in 1844. Carrying on the family business, after the deaths of his father and brother, Clark made the 40" lenses of the Yerkes telescope (still the largest refractor in operation in the world). Their safe delivery was a source of anxiety. He died shortly after their first use.




1969 Harold Davenport (30 October 1907 – 9 June 1969) worked on number theory, in particular the geometry of numbers, Diophantine approximation and the analytic theory of numbers. He wrote a number of important textbooks and monographs including The higher arithmetic (1952)*SAU

While most sources credit Richard von Mises with creating the "Birthday Problem", I have found sources that credit Harold Davenport with creating the problem,.





1977 Dr. Gustav Doetsch (November 29, 1892 – June 9, 1977) was a German mathematician, aviation researcher, decorated war veteran, and Nazi supporter. The modern formation and permanent structure of the Laplace transform is found in Doetsch's 1937 work Theorie und Anwendung der Laplace-Transformation,[5] which was well-received internationally. He dedicated most of his research and scientific activity to the Laplace transform, and his books on the subject became standard texts throughout the world, translated into several languages. His texts were the first to apply the Laplace transform to engineering. *Wik




1994 Jan Tinbergen (April 12, 1903 – June 9, 1994), was a Dutch economist. He was awarded the first Bank of Sweden Prize in Economic Sciences in Memory of Alfred Nobel in 1969, which he shared with Ragnar Frisch for having developed and applied dynamic models for the analysis of economic processes. Tinbergen was a founding trustee of Economists for Peace and Security.
Tinbergen became known for his 'Tinbergen Norm', which is the principle that, if the difference between the least and greatest income in a company exceeds a rate of 1:5, that will not help the company and may be counterproductive.*Wik



1995  Vivienne Lucille Malone-Mayes (February 10, 1932 – June 9, 1995) was an American mathematician and professor. Malone-Mayes studied properties of functions, as well as methods of teaching mathematics. She was the fifth African-American woman to gain a PhD in mathematics in the United States, and the first African-American member of the faculty of Baylor University (which had rejected her application to study there five years earlier).
She decided to attend the University of Texas full-time as a graduate student when rejected entry at Baylor. In graduate school she was very much alone. In her first class, she was the only Black, the only woman. Her classmates ignored her completely, even terminating conversations if she came within earshot. She was denied a teaching assistantship, although she was an experienced and excellent teacher.
She wrote, "... it took a faith in scholarship almost beyond measure to endure the stress of earning a Ph.D. degree as a Black, female graduate student. I could not join my advisor and other classmates to discuss mathematics over coffee at Hilsberg's cafe .... Hilsberg's would not serve Blacks.
Some classes were closed to her despite the fact that the University of Texas was required to take Black students. For example R L Moore refused to have any Black students in his classes.
She was a member of the board of directors of the National Association of Mathematicians. She was elected Director-at-large for the Texas section of Mathematical Association of America and served as director of the High School Lecture Program for the Texas section.
She had a successful, lengthy career and served on several boards and committees of note, retiring in 1994 due to ill health.  She was the fifth African-American woman to be allowed in the White House.She was also active in her local community as a lifetime member of New Hope Baptist Church. She served on boards of directors for Cerebral Palsy, Goodwill Industries, and Family Counseling and Children. She was on the Texas State Advisory Council for Construction of Community Mental Health Centers and served on the board of the Heart of Texas Region Mental Health and Mental Retardation Center.
After Lillian K. Bradley in 1960, Malone-Mayes became one of the first African-American women to receive a PhD in Mathematics from University of Texas (and fifth African-American woman in the United States). She was the first African-American member of the faculty at Baylor University, and the first African-American person elected to Executive Committee of the Association of Women in Mathematics.
The student congress of Baylor voted her the "Outstanding Faculty Member of the Year" in 1971.  *Wik & *SAU

*Wik




Credits :
*CHM=Computer History Museum
*FFF=Kane, Famous First Facts
*NSEC= NASA Solar Eclipse Calendar
*RMAT= The Renaissance Mathematicus, Thony Christie
*SAU=St Andrews Univ. Math History
*TIA = Today in Astronomy
*TIS= Today in Science History
*VFR = V Frederick Rickey, USMA
*Wik = Wikipedia
*WM = Women of Mathematics, Grinstein & Campbell