//pi \ \ lim ||-- - x|*tan(x)| x->pi+\\2 / /
Limit((pi/2 - x)*tan(x), x, pi)
0
= 1.92367069372179e-16
//pi \ \ lim ||-- - x|*tan(x)| x->pi-\\2 / /
= 1.92367069372184e-16
1.92367069372179e-16