_______ ___ _______ \/ x + 1 - \/ x < \/ x - 1
-sqrt(x) + sqrt(x + 1) < sqrt(x - 1)
/ ___ \ |2*\/ 3 | And|------- < x, x < oo| \ 3 /
(x < oo)∧(2*sqrt(3)/3 < x)
___ 2*\/ 3 (-------, oo) 3
x in Interval.open(2*sqrt(3)/3, oo)