I'm beginning to wonder if this should be controlled by a flag, since in
many cases, the ability to effectively simplify large and complex
expressions far outweighs the mathematical "purity" of a derivative defined
without removable singularities.
Viktor
-----Original Message-----
From: Barton Willis [mailto:willisb at unk.edu]
Sent: Tuesday, May 20, 2008 6:30 PM
To: Viktor T. Toth
Cc: 'Oliver Kullmann'; maxima at math.utexas.edu
Subject: RE: [Maxima] Lambert W function?
-----"Viktor T. Toth" <vttoth at vttoth.com> wrote: -----
>Maple:
>> LambertW(x)/diff(LambertW(x),x);
> (1 + LambertW(x)) x
>
>Maxima:
>(%i1) lambert_w(x)/diff(lambert_w(x),x);
> lambert_w(x)
>(%o1) lambert_w(x) (lambert_w(x) + 1) %e
>
>This makes it much harder to simplify complicated expressions that involve
>both Lambert's W and its derivative. (In particular, I ran across it when
>constructing a metric in ctensor that involved Lambert's W.)
It's a problem---a ratsubst will clean up simple cases. But it's a pain.
I don't know of a good general solution.
Barton