Re: [Maxima-discuss] fourie.mac package fails for simple square wave

[Robert D. <rob...@gm...>]

On Sat, Mar 16, 2024 at 1:51 PM Majzoub, Eric <eri...@um...> wrote:

> So maybe ldefint() needs to be looked into?

Eric, thanks for bringing up the whole business about fourier. Indeed
I believe that ldefint (which is, for the record, a built-in function
to compute integrals via limits) is the path through which the problem
appears in fourier, however, I believe the problem is not in ldefint
itself, but rather in limit. I've opened a bug report about it:
https://sourceforge.net/p/maxima/bugs/4273/

What I'm seeing is that limit(integrate(f(x)*g(x), x), x, a) yields
just integrate(f(x)*g(x), x) (losing the limit) when f and g are both
built-in simplifying functions. E.g.

limit (integrate (abs(x) * exp(x), x), x, a);
 => 'integrate(abs(x)*exp(x), x)

Other examples are shown in the bug report.

I haven't investigated what's going on there, I'll let you know if I
figure something out.

best

Robert