The Symbol for Natural Log
Date: 06/28/2000 at 23:57:20 From: Adam Abrams Subject: Natural law Why is natural log abbreviated as "ln" and not "nl?" Please, I am just curious. Adam Abrams
Date: 06/29/2000 at 12:56:17 From: Doctor Rick Subject: Re: Natural law Hi, Adam. According to Jeff Miller's "Earliest Uses of Various Mathematical Symbols" (which you can find from our Dr. Math FAQ page) at: http://jeff560.tripod.com/mathsym.html the symbol "ln" first appeared here: "ln (for natural logarithm) was used in 1893 by Irving Stringham (1847-1909) in _Uniplanar_Algebra_." His name doesn't sound French, but my theory is that there is a French influence in this and other naming conventions. In French, the modifier "natural" would follow the noun "logarithm." In the same way, the International System of Units is called the SI, not the IS, because in French it's Systeme International d'Unites. French influence or not, the way we use subscripts follows the same pattern. A subscript modifies the meaning of the main variable, and we put it *after* the variable. For instance, Avogadro's number is called N_A (N-subscript-A), not A_N; the A for Avogadro qualifies the N, and it is put after the N. This way of writing is very natural to mathematicians; it makes sense to put the more general first, and the qualifiers or the more specific after. "What are you talking about?" "Logarithms!" "What KIND of logarithm?" "Natural!" So the notion of writing "nl" seems very odd to me, and "ln" is more natural (no pun intended). - Doctor Rick, The Math Forum http://mathforum.org/dr.math/
Search the Dr. Math Library:
Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.