History of the Radical Sign
Date: 04/17/97 at 10:26:17 From: Marc Younger Subject: Radical sign Who invented the radical sign?
Date: 04/17/97 at 14:10:37 From: Doctor Bombelli Subject: Re: Radical sign A wonderful source for this type of question is _A History of Mathematical Notation_ by Florian Cajori, from which the following is taken: The word "radix" was used for square root in the thirteenth century or so, and was abbreviated as "R" or R with a slash though the right leg of the R, like the Rx symbol at pharmacies. The symbol that looks like a check (radical sign without the "roof") originated in Germany, in the 1500's. It started out looking quite like a musical note. If you had a long expression under the radical sign, the expression was put in parentheses, and later, placed with a line over it. This is where the current symbol came from. Descartes in his _La Geometrie_ (1637) seems to be the first to place the line on top for grouping. So, no one really "invented" the sign - it developed over the years. But if you need a specific person, Descartes seems to be the one to first use the present day version of the symbol -Doctor Bombelli, The Math Forum Check out our web site! http://mathforum.org/dr.math/
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