Problem with IS and EQUAL in evaluating equality of expressions



The function 'zeroequiv' claims to try a bit harder
than does 'is(equal( ...))'.  If you search the list
and the bug list, I think you'll discover that
zeroequiv is unworthy of being in /src.  Here is
an example that works OK:

(%i1) load("zero")$
(%i2) zeroequiv(cos(x)^2 + sin(x)^2-1,x);
(%o2)                              true  <--- OK

The required second argument is a puzzler--how can
an expression vanish with respect to one variable, but
not another? That's bogus.  We really should do better.

Barton