What is the story of taxicab numbers?



Are you aware of numbers that are called as taxicab numbers? The nth taxicab number is the smallest number representable in n different ways as a sum of two positive integer cubes. These numbers are also called as the Hardy-Ramanujan number. The name taxicab numbers, in fact is derived from a story told about Indian mathematician Srinivasa Ramanujan by English mathematician GH Hardy. Here is the story, as told by Hardy I remember once going to see him (Ramanujan) when he was lying ill at Putney. I had ridden in taxi-cab No. 1729, and remarked that the number seemed to be rather a dull one, and that I hoped it was not an unfavourable omen. "No," he replied, "it is a very interesting number, it is the smallest number expressible as the sum of two [positive] cubes in two different ways."



1729, naturally, is the most popular taxicab number. 1729 can be expressed as the sum of both 12^3 and 1^3 (1728+1) and as the sum of 10 and 9 (1000+729).



While the story involving Ramanujan made these numbers famous and also gave it its name. these numbers were actually known earlier. The first mention of this concept can be traced back to the 17th Century.



2 (1^3 + 1^3) is the first taxicab number and 1729 is the second. The numbers after 1729 have been found out using computers and six taxicab numbers are known so far.



 



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What is the product of all the numbers that appear in the dial pad of our mobile phones?



Since one of the numbers on the dial of a telephone is zero, so the product of all the numbers on it is 0.



The layout of the digit keys is different from that commonly appearing on calculators and numeric keypads. This layout was chosen after extensive human factors testing at Bell Labs. At the time (late 1950s), mechanical calculators were not widespread, and few people had experience with them. Indeed, calculators were only just starting to settle on a common layout; a 1955 paper states "Of the several calculating devices we have been able to look at... Two other calculators have keysets resembling [the layout that would become the most common layout].... Most other calculators have their keys reading upward in vertical rows of ten," while a 1960 paper, just five years later, refers to today's common calculator layout as "the arrangement frequently found in ten-key adding machines". In any case, Bell Labs testing found that the telephone layout with 1, 2, and 3 in the top row, was slightly faster than the calculator layout with them in the bottom row.



The key labeled ? was officially named the "star" key. The original design used a symbol with six points, but an asterisk (*) with five points commonly appears in printing.[citation needed] The key labeled # is officially called the "number sign" key, but other names such as "pound", "hash", "hex", "octothorpe", "gate", "lattice", and "square", are common, depending on national or personal preference. The Greek symbols alpha and omega had been planned originally.



These can be used for special functions. For example, in the UK, users can order a 7:30 am alarm call from a BT telephone exchange by dialing: *55*0730#.



 



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What is a zero in math?



Do you have a mathematics teacher who writes a big fat zero that occupies the entire blackboard whenever an answer boils down to it? None of us wish to see it on our answer sheets (unless, of course, it is for 100). but zero fascinates and frustrates maths lovers and haters in equal measures. Even though civilisations have always understood the concept of nothing or having nothing. India is generally credited with developing the numerical zero. It is hard for us to imagine a world without zero, and it is no wonder therefore that giving zero a symbol is seen as one of the greatest innovations in human history. Without this zero, modem mathematics, physics and technology would all probably zero down to nothing! The philosophy of emptiness or shunya (shunya is zero in Sanskrit) is believed to have been an important cultural factor for the development of zero in India. The concept is said to have been fully developed by the 5th Century. and maybe even earlier.



The Bakhshali manuscript, discovered in a field in 1881, is currently seen as the earliest recorded use of a symbol for zero. Dating techniques place this manuscript to be written anywhere between the 3rd and 9th Century.



 



Picture Credit : Google