Firstly I suggest you change your calculation, whatever it is,
to use log, the natural log.
Secondly, you can make it possible to type log10(x) by
defining log10(x):=log(x)/log(10).
This will, of course, merely wipe out log10 in favor of log
forever. It will also make everything that works with log
work with log10, except the printout.
It is usually considered a bad thing to have a multiplicity of
ways to represent the same thing. Maxima has a number
of such functions, e.g. cos(x) and 1/sec(x) are the same. Do
you really want them both? Maxima has
exp(-x) and 1/exp(x) and %e^(-x). Try typing them in.
This particular multiplicity of representation was considered
too fundamental and too intolerable.
So while it is possible to introduce log10 into Maxima, and
make it work -- maybe even make it work perfectly for all
the things you do, even differentiation -- it would undoubtedly
cause difficulties. Teaching the differentiation rule for log10
is easy -- read about gradef. Making log10 work for more
advanced operation would be tedious, unless you just defined
it in terms of log.
So although it undoubtedly sounds elitist or worse, I think
the most useful advice is to not use log10 inside Maxima at all,
and take the advice of the people who wrote it, and just use
log.
RJF
----- Original Message -----
From: "Hugo Coolens" <coolens at kahosl.be>
To: "Mario Rodriguez" <biomates at telefonica.net>
Cc: "Robert Dodier" <robert.dodier at gmail.com>; <maxima at math.utexas.edu>
Sent: Saturday, March 11, 2006 5:16 AM
Subject: Re: [Maxima] newbie question about log10
> Even though log10(100) now gives me the expected result.
> diff(log10(x),x) doesn't give me (1/(x log(x)))
> but just repeats the expressing entered. How should I proceed to make
> maxima give me the expected result?
>
> regards,
> hugo
>
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