Intelligent approach for differentiation through sums?

On 2013-02-19, Mike Valenzuela <mickle.mouse at gmail.com> wrote:

> I am trying to figure out how to implement some rules that will allow
> differentiation under (finite) sums.

I think tellsimp is a workable approach. The hard part is probably
convincing Maxima not to simplify diff(foo, bar) --> 0 when foo doesn't
explicitly depend on bar. You might try stating rules for, say, mydiff
instead of diff (i.e. you control all the rules and there are no
built-ins) and then simplifying or substituting mydiff --> diff at the
end. I am interested in problems like this but unfortunately I may not
have much time to devote to it. Keep me posted all the same.

best

Robert Dodier