Origin of the Factorial Symbol !
Date: 01/14/2002 at 06:44:04 From: Julia Kolb Subject: Origin of mathematical symbol ! My students would like to know the origin of the mathematical symbol for factorial - !. Furthermore, was the symbol used as an exclamation mark in writing before it was used as a mathematical symbol?
Date: 01/14/2002 at 07:19:52 From: Doctor Peterson Subject: Re: Origin of mathematical symbol ! Hi, Julia. The Dr. Math FAQ includes a link to Earliest Uses of Mathematical Symbols http://jeff560.tripod.com/mathsym.html which is a great site to answer questions about the origin of math symbols. If you look up "!" there (under "probability and statistics"), you find that the symbol was used in place of an earlier notation that was less convenient for printers. The exclamation mark was already in use as punctuation, so printers did not need to add a special symbol. (It sounds like what we do these days using punctuation like "*" and "^" to avoid needing special fonts in e-mail.) The article quotes a complaint about this usage of symbols that already meant something: In his article "Symbols" in the Penny Cyclopaedia (1842) De Morgan complained: "Among the worst of barabarisms is that of introducing symbols which are quite new in mathematical, but perfectly understood in common, language. Writers have borrowed from the Germans the abbreviation n! to signify 1.2.3.(n - 1).n, which gives their pages the appearance of expressing surprise and admiration that 2, 3, 4, &c. should be found in mathematical results." I have to admit I often feel the same way! (Symbolic pun not intended.) - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/
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