Some Question



Hi
I am a new user for maxima, I use teXmac interface. I want to know the
following:

1) How to write comment in maxima session in texmac?
2) How to save file and reopen it using texmac? 
3) I have a function like this:

   f(r) = diff(v(r),r);

   How to write this? In maple I write:  
  f(r) = subs(s=r,diff(v(s),s)); which substitute s with r after
differentiation.

4) Is there any basic documentation where I can get the answare of such trivial
   thing?

With Regards
Tapan