Published September 3, 2015
Tags: Algebra, History
James Joseph Sylvester (1814-1897) as a graduate of Trinity College Dublin.
James Joseph Sylvester was born in London to Jewish parents in 1814, just 201 years ago today. The family name was Joseph but, for reasons unclear, Sylvester – the name of an anti-Semitic Pope from the Roman period – was adopted later. [TM075; or search for “thatsmaths” at irishtimes.com ]
Sylvester’s mathematical talents became evident at an early age. He entered Cambridge in 1831, aged just seventeen and came second in the notorious examinations known as the Mathematical Tripos; the man who beat him achieved nothing further in mathematics!
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Published August 27, 2015
Tags: Astronomy, History
Sir Walter Raleigh, adventurer, explorer and privateer, was among most colourful characters of Tudor times. He acquired extensive estates in Waterford and Cork, including Molana Abbey near Youghal, which he gave to his friend and advisor, the brilliant mathematician and astronomer Thomas Harriot.
Left: Sir Walter Raleigh (1552-1618). Right: Thomas Harriot (1560?-1621)
Continue reading ‘Thomas Harriot: Mathematician, Astronomer and Navigator’
Just two years from now, on Monday, August 21, 2017, the Moon’s shadow will sweep across the United States at a speed of over 2,000 km/hr. The Great American Eclipse of 2017 will generate a frenzy of activity. [TM074: search for “thatsmaths” at irishtimes.com ].
Moon between NASA’s Solar Dynamics Observatory and the Sun,
giving a partial solar eclipse from space on Jan. 30, 2014. Image NASA.
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Published August 13, 2015
Tags: Algorithms, Probability
The Buffon Needle method of estimating is hopelessly inefficient. With one million throws of the needle we might expect to get an approximation accurate to about three digits. The idea is more of philosophical than of practical interest. Buffon never envisaged it as a means of computing .
Continue reading ‘Buffon was no Buffoon’
Image drawn with Mathematica package in: Siniksaran, Erin, 2008: Throwing Buffon’s Needle [Reference below].
Published August 4, 2015
Tags: Algorithms, Euler, Topology
Leonhard Euler considered a problem known as The Seven Bridges of Königsberg. It involves a walk around the city now known as Kaliningrad, in the Russian exclave between Poland and Lithuania. Since Kaliningrad is out of the way for most of us, let’s have a look closer to home, at the bridges of Paris. [TM073: search for “thatsmaths” at irishtimes.com ]
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The idea of using two numbers to identify a position on the Earth’s surface is very old. The Greek astronomer Hipparchus (190–120 BC) was the first to specify location using latitude and longitude. However, while latitude could be measured relatively easily, the accurate determination of longitude was more difficult, especially for sailors out of site of land.
OSi Mapviewer. XY coordinates indicated at bottom left.
French philosopher, scientist and mathematician René Descartes demonstrated the power of coordinates and his method of algebraic geometry revolutionized mathematics. It had a profound, unifying effect on pure mathematics and greatly increased the ability of maths to model the physical world.
Continue reading ‘Who Needs EirCode?’
Published July 23, 2015
If we toss a `fair’ coin, one for which heads and tails are equally likely, a large number of times, we expect approximately equal numbers of heads and tails. But what is `approximate’ here? How large a deviation from equal values might raise suspicion that the coin is biased? Surely, 12 heads and 8 tails in 20 tosses would not raise any eyebrows; but 18 heads and 2 tails might.
Continue reading ‘Bent Coins: What are the Odds?’