green's functions, passing functions to a routine

> in your program. An easy workaround is to name the formal argument
> something obscure like f% or whatever.
  Thats odd. I can do this though.


> >    h1(x,t) := ''(ratsimp(integrate(g1(x,t),t)));
>
> Probably better to write
>
> define (h1 (x, t), ratsimp (integrate (g1 (x, t), t)));

     Thats good to know

> At present integrate, diff, etc know nothing about functions defined
> piecewise. I've tinkered with some pattern-matching rules to tell
> integrate how to handle such functions. I'll try to dig out the code I
> wrote --- I don't think I got very far.

That would be good in general. For now I am doing it by hand. 
The Green's function integral is defined piecewise to begin with.
Evaluating it with a piecewise-defined inhomogeneous term as well
can make my head hurt if I'm tired. It would be nice if Maxima could
do it for me, but there are a bunch of things to work on....

> Incidentally the integral should be expressed as: integrate (f (x), x, 0,
> 4);
  Right, it was done correctly in my code.