On 2/15/12, Stavros Macrakis <macrakis at alum.mit.edu> wrote:
> diff(x,tan(x)) => 0
> diff(x,f(x)) => 0
>
> but not
>
> diff(x,1+x) => error
>
> In principle, all of these could of course be meaningful, but Maxima
> doesn't know that.
>
> Which seems more useful for users in such cases?:
>
> * Giving an error?
> * Leaving as noun forms? (which Maxima can't do anything useful with)
Well, in general it seems useful, and consistent with Maxima's
behavior in other cases, to return a noun form. Then sufficiently
clever people (whether it's the developers or anybody else) can
impose an interpretation of such expressions via the simplification
system.
An error might be appropriate for cases in which Maxima has
determined that the expression is undefined.
best,
Robert Dodier