/ 1 \ lim atan|-------| x->1+ | 2| \-1 + x /
Limit(atan(1/(-1 + x^2)), x, 1)
pi -- 2
= 1.5707963267949
/ 1 \ lim atan|-------| x->1- | 2| \-1 + x /
-pi ---- 2
= -1.5707963267949
1.5707963267949