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| | Hello, dear friend! My name is Christena. I smile that I can unify to the entire world. I live in Austria, in the south region. I dream to go to the various countries, to obtain acquainted with interesting individuals.<br><br>Take a look at my web page; [http://fccgarrison.com/?attachment_id=16 Fifa 15 Coin Generator] |
| [[File:Dase.jpg|right|160px|thumb|Johann Dase]]
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| '''Johann Martin Zacharias Dase''' (June 23, 1824, [[Hamburg]] - September 11, 1861, Hamburg) was a German [[mental calculator]].<ref name="rouse_ball_1960">[[W. W. Rouse Ball]] (1960) ''Calculating Prodigies'', in Mathematical Recreations and Essays, Macmillan, New York, chapter 13.</ref>
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| He attended schools in Hamburg from a very early age, but later admitted that his instruction had little influence on him. He used to spend a lot of time playing [[dominoes]], and suggested that this played a significant role in developing his calculating skills. Dase suffered from [[epilepsy]] from early childhood throughout his life.
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| At age 15 he began to travel extensively, giving exhibitions in Germany, Austria and England. Among his most impressive feats, he multiplied 79532853 × 93758479 in 54 seconds. He multiplied two 20-digit numbers in 6 minutes; two 40-digit numbers in 40 minutes; and two 100-digit numbers in 8 hours 45 minutes. The famous mathematician [[Carl Friedrich Gauss]] commented that someone skilled in calculation could have done the 100-digit calculation in about half that time with pencil and paper.
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| These exhibitions however did not earn him enough money, so he tried to find other employments. In 1844 he obtained a position in the Railway Department of Vienna, but this didn't last long since in 1845 he was reported in Mannheim and in 1846 in Berlin.
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| In 1844, Dase calculated [[π]] to 200 decimal places in his head, a record for the time, from the [[Machin-like formula]]:
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| :<math>\frac{\pi}{4} = \arctan \frac{1}{2} + \arctan \frac{1}{5} + \arctan \frac{1}{8}.</math>
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| He also calculated a 7-digit [[logarithm table]] and extended a table of [[integer factorization]]s from 7,000,000 to 10,000,000.
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| Dase had very little knowledge of mathematical theory. The mathematician [[Julius Petersen]] tried to teach him some of [[Euclid]]'s theorems, but gave up the task once he realized that their comprehension was beyond Dase's capabilities.
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| Gauss however was very impressed with his calculating skill, and he recommended that the ''Hamburg Academy of Sciences'' should allow Dase to do mathematical work on a full-time basis, but Dase died shortly thereafter.
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| The book "[[Gödel, Escher, Bach]]" by [[Douglas Hofstadter]] mentions his calculating abilities. "... he also had an uncanny sense of quantity. That is, he could just 'tell', without counting, how many sheep were in a field, or words in a sentence, and so forth, up to about 30."
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| ==References==
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| {{Reflist}}
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| ==External links==
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| * [http://www-history.mcs.st-and.ac.uk/Biographies/Dase.html] - A biography of Zacharias Dase.
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| {{Persondata <!-- Metadata: see [[Wikipedia:Persondata]]. -->
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| | NAME = Dase, Zacharias
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| | ALTERNATIVE NAMES =
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| | SHORT DESCRIPTION =
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| | DATE OF BIRTH = June 23, 1824
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| | PLACE OF BIRTH =
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| | DATE OF DEATH = September 11, 1861
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| | PLACE OF DEATH =
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| }}
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| {{DEFAULTSORT:Dase, Zacharias}}
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| [[Category:Mental calculators]]
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| [[Category:1824 births]]
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| [[Category:1861 deaths]]
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Hello, dear friend! My name is Christena. I smile that I can unify to the entire world. I live in Austria, in the south region. I dream to go to the various countries, to obtain acquainted with interesting individuals.
Take a look at my web page; Fifa 15 Coin Generator