The Term PowerDate: 10/23/2001 at 13:33:44 From: Toni Delvecchio Subject: Exponents One of my students asked how we came to use the term power to express the number of times we multiply a number by itself. I searched your link provided by Jeff Miller on mathematical terms, but didn't find a good explanation of its origin. Can you give us a good explanation? Thank You, T. DelVecchio 6th gr. teacher Birch Lane School Date: 10/23/2001 at 15:00:26 From: Doctor Rob Subject: Re: Exponents Thanks for writing to Ask Dr. Math, Toni. I looked in Smith's _History of Mathematics_, vol. II, pp. 393-394. Apparently this goes back to the Greek geometric algebra. They used the word "dynamis" which translates in English to "power." (Compare the English words "dynamic" and "dynamo," from the same root.) I don't think anyone knows why the Greeks chose that word, the reasons being lost in the mists of time. Perhaps it has something to do with the fact that x^n grows faster than x^(n-1), as x increases, and so is thought of as more powerful. This is just a personal guess. From Pat Ballew's Math Words, and Some Other Words of Interest: http://www.geocities.com/Paris/Rue/1861/etyindex.html POWER The word power comes from the French poeir and perhaps the earlier Latin word potere from which we get potent. Both words refer to ability or being able. In mathematics, power refers to the number arrived at by raising a number to an exponent. In the mathematical expression 3^2 = 9, three is the base, two is the exponent, and nine is the power. Students often refer to the exponent as the power, but this is not historically correct, although it has become so common, even among many teachers, that some dictionaries refer to the power as the exponent. From Jeff Miller's Web page on the first use of some math words I found that "POWER appears in English in 1570 in Sir Henry Billingsley's translation of Euclid's Elements: 'The power of a line, is the square of the same line.' ." - Doctor Rob, The Math Forum http://mathforum.org/dr.math/ |
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