Re: [Axiom-developer] Expression problems

[Martin Rubey]

Francois Maltey <address@hidden> writes:

> Hello everybody ! Hans, Bill and others...
> 
> > I am struggling with dealing with Expressions. For most sake and purposes I 
> > can find a fix and solve my small problems, but I never feel very assured.
> 
> I have the same problem when I try to expand cos(2*x) in cos(x)^2-sin(x)^2.
> 
> The expand(cos(x+y)) is right, but expand (cos(2*x)) remains cos(2*x).
> 
> Martin and Bill help me, but I can't see the pretty way to write
> my own expand which also compute for cos(2*x).

I believe that the "correct" way to do this is to patch the existing domains.

You did not respond to 

http://lists.nongnu.org/archive/html/axiom-developer/2005-06/msg00294.html

so I thought that you managed to get the results you wanted. Are you able to
program in SPAD or Aldor already? I can help, if necessary. 

Maybe you could find out where the code for Chebyshev expansion should be
inserted, possibly using the )trace facility - also described on MathAction:
look at DebuggingAxiom.

WE NEED MORE ALGEBRA DEVELOPERS!

Martin