simplification of atan(tan(x)), etc



> It is also true of the mod expression, assuming the expression is right,
> but how clever would the simplifier have to be to know that
> tan (mod (....))   was tan(x)?

SIMP-NUMMOD (which handles simplification of mod) does not appear
to know that mod (x, FOO) yields x when is(x > 0 and x < FOO) => true,
although i believe it should be straightforward to put that in.

> Another possibility is to ask the user if   -pi/2<x<pi/2  before doing
> the simplification, but people don't seem to like ASKSIGN.

for the record: i am opposed to putting in additional instances of asksign
(and i'd like to get rid of the existing ones).

robert