say we have a function $f:\mathbb R^3 \to \mathbb R$ given by
$f(x,y,z)=\sin(x)\sin(y)\sin(z)$
suppose further that there constraints $x,y,z \in (0, \pi/2)$ and $z>x+y$.
Clearly this function is nonvanishing with these constraints. Is there a way to get sage to show this? I've tried fiddling around, but I'm not sure how to do it.