On Jun 23, 3:52 am, Steven D'Aprano <ste...@remove.this.cybersource.com.au> wrote: > On Mon, 22 Jun 2009 13:43:19 -0500, David C. Ullrich wrote: > > In my universe the standard definition of "log" is different froim what > > log means in a calculus class > > Now I'm curious what the difference is.
It's just the usual argument about whether 'log' means log base 10 or log base e (natural log). At least in the US, most[*] calculus texts (and also most calculators), for reasons best known to themselves, use 'ln' to mean natural log and 'log' to mean log base 10. But most mathematicians use 'log' to mean natural log: pick up a random pure mathematics research paper that has the word 'log' in it, and unless it's otherwise qualified, it's safe to assume that it means log base e. (Except in the context of algorithmic complexity, where it might well mean log base 2 instead...) Python also suffers a bit from this confusion: the Decimal class defines methods 'ln' and 'log10', while the math module and cmath modules define 'log' and 'log10'. (But the Decimal module has other problems, like claiming that 0**0 is undefined while infinity**0 is 1.) [*] A notable exception is Michael Spivak's 'Calculus', which also happens to be the book I learnt calculus from many years ago. Mark -- http://mail.python.org/mailman/listinfo/python-list
