Professor Ted Titchmarsh  

Born  Edward Charles Titchmarch 1 June 1899 
Died  18 January 1963 Oxford, Oxfordshire, England  (aged 63)
Nationality  British 
Alma mater  Balliol College, Oxford 
Known for  Brun–Titchmarsh theorem Titchmarsh convolution theorem Titchmarsh theorem (on the Hilbert transform) Titchmarsh–Kodaira formula 
Awards  De Morgan Medal (1953) Sylvester Medal (1955) Senior Berwick Prize (1956) Fellow of the Royal Society^{[1]} 
Scientific career  
Academic advisors  G. H. Hardy^{[2]} 
Doctoral students  Lionel Cooper John Bryce McLeod^{[2]} 
Edward Charles "Ted" Titchmarsh (June 1, 1899 – January 18, 1963) was a leading English mathematician.^{[1]}^{[2]}^{[3]}
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✪ How many ways are there to prove the Pythagorean theorem?  Betty Fei

✪ Mathematical physics

✪ Fourier transform
Transcription
What do Euclid, twelveyearold Einstein, and American President James Garfield have in common? They all came up with elegant proofs for the famous Pythagorean theorem, the rule that says for a right triangle, the square of one side plus the square of the other side is equal to the square of the hypotenuse. In other words, a²+b²=c². This statement is one of the most fundamental rules of geometry, and the basis for practical applications, like constructing stable buildings and triangulating GPS coordinates. The theorem is named for Pythagoras, a Greek philosopher and mathematician in the 6th century B.C., but it was known more than a thousand years earlier. A Babylonian tablet from around 1800 B.C. lists 15 sets of numbers that satisfy the theorem. Some historians speculate that Ancient Egyptian surveyors used one such set of numbers, 3, 4, 5, to make square corners. The theory is that surveyors could stretch a knotted rope with twelve equal segments to form a triangle with sides of length 3, 4 and 5. According to the converse of the Pythagorean theorem, that has to make a right triangle, and, therefore, a square corner. And the earliest known Indian mathematical texts written between 800 and 600 B.C. state that a rope stretched across the diagonal of a square produces a square twice as large as the original one. That relationship can be derived from the Pythagorean theorem. But how do we know that the theorem is true for every right triangle on a flat surface, not just the ones these mathematicians and surveyors knew about? Because we can prove it. Proofs use existing mathematical rules and logic to demonstrate that a theorem must hold true all the time. One classic proof often attributed to Pythagoras himself uses a strategy called proof by rearrangement. Take four identical right triangles with side lengths a and b and hypotenuse length c. Arrange them so that their hypotenuses form a tilted square. The area of that square is c². Now rearrange the triangles into two rectangles, leaving smaller squares on either side. The areas of those squares are a² and b². Here's the key. The total area of the figure didn't change, and the areas of the triangles didn't change. So the empty space in one, c² must be equal to the empty space in the other, a² + b². Another proof comes from a fellow Greek mathematician Euclid and was also stumbled upon almost 2,000 years later by twelveyearold Einstein. This proof divides one right triangle into two others and uses the principle that if the corresponding angles of two triangles are the same, the ratio of their sides is the same, too. So for these three similar triangles, you can write these expressions for their sides. Next, rearrange the terms. And finally, add the two equations together and simplify to get ab²+ac²=bc², or a²+b²=c². Here's one that uses tessellation, a repeating geometric pattern for a more visual proof. Can you see how it works? Pause the video if you'd like some time to think about it. Here's the answer. The dark gray square is a² and the light gray one is b². The one outlined in blue is c². Each blue outlined square contains the pieces of exactly one dark and one light gray square, proving the Pythagorean theorem again. And if you'd really like to convince yourself, you could build a turntable with three square boxes of equal depth connected to each other around a right triangle. If you fill the largest square with water and spin the turntable, the water from the large square will perfectly fill the two smaller ones. The Pythagorean theorem has more than 350 proofs, and counting, ranging from brilliant to obscure. Can you add your own to the mix?
Contents
Education
Titchmarsh was educated at King Edward VII School (Sheffield) and Balliol College, Oxford, where he began his studies in October 1917.
Career
Titchmarsh was known for work in analytic number theory, Fourier analysis and other parts of mathematical analysis. He wrote several classic books in these areas; his book on the Riemann zetafunction was reissued in an edition edited by Roger HeathBrown.
Titchmarsh was Savilian Professor of Geometry at the University of Oxford from 1932 to 1963. He was a Plenary Speaker at the ICM in 1954 in Amsterdam.
He was on the governing body of Abingdon School from 19351947.^{[4]}
Awards
 Fellow of the Royal Society, 1931^{[1]}
 De Morgan Medal, 1953
 Sylvester Medal, 1955
 Berwick Prize winner, 1956
Publications
 The ZetaFunction of Riemann (1930);
 Introduction to the Theory of Fourier Integrals (1937)^{[5]} 2nd. edition(1939) 2nd. edition (1948);
 The Theory of Functions (1932);^{[6]}
 Mathematics for the General Reader (1948);
 The Theory of the Riemann ZetaFunction (1951);^{[7]} 2nd edition, revised by D. R. HeathBrown (1986)
 Eigenfunction Expansions Associated with Secondorder Differential Equations. Part I (1946)^{[8]} 2nd. edition (1962);
 Eigenfunction Expansions Associated with Secondorder Differential Equations. Part II (1958);^{[9]}
References
 ^ ^{a} ^{b} ^{c} Cartwright, M. L. (1964). "Edward Charles Titchmarsh 18991963". Biographical Memoirs of Fellows of the Royal Society. 10: 305–326. doi:10.1098/rsbm.1964.0018.
 ^ ^{a} ^{b} ^{c} Edward Charles Titchmarsh at the Mathematics Genealogy Project
 ^ O'Connor, John J.; Robertson, Edmund F., "Edward Charles Titchmarsh", MacTutor History of Mathematics archive, University of St Andrews.
 ^ "School Notes" (PDF). The Abingdonian.
 ^ Tamarkin, J. D. (1938). "Review: Introduction to the Theory of Fourier Integrals by E. C. Titchmarsh" (PDF). Bull. Amer. Math. Soc. 44 (11): 764–765. doi:10.1090/s000299041938068760.
 ^ Chittenden, E. W. (1933). "Review: The Theory of Functions by E. C. Titchmarsh" (PDF). Bull. Amer. Math. Soc. 39 (9): 650–651. doi:10.1090/s000299041933056902.
 ^ Levinson, N. (1952). "Review: The theory of the Riemann zetafunction by E. C. Titchmarsh" (PDF). Bull. Amer. Math. Soc. 58 (3): 401–403. doi:10.1090/s000299041952095926.
 ^ Trjitzinsky, W. J. (1948). "Review: Eigenfunction expansions associated with secondorder differential equations by E. C. Titchmarsh" (PDF). Bull. Amer. Math. Soc. 54 (5): 485–487. doi:10.1090/s000299041948090012.
 ^ Hartman, Philip (1959). "Review: Eigenfunction expansions associated with secondorder differential equations, Part 2 by E. C. Titchmarsh" (PDF). Bull. Amer. Math. Soc. 65 (3): 151–154. doi:10.1090/s000299041959103074.