Illustration of what I mean by "work too hard to try to apply the
even / odd function simplifications"
(%i1) assume(x<0);
(%o1) [x < 0]
(%i2) sin(x);
(%o2) - SIN(- x)
It seems gratuitous to apply the odd function rule in this case. We need
a reasonable heuristic for deciding when to apply the even / odd
function rules. I don't know what it would be.
Barton