x≠±1
求导:
y'=1+[1*(x^2-1)-x*(2x)]/(x^2-1)^2
=1+(-x^2-1)/(x^2-1)^2
=[(x^2-1)^2-(x^2+1)]/(x^2-1)^2
=(x^4-3x^2)/(x^2-1)^2
=x^2(x^2-3)/(x^2-1)^2
y'=0,x=0,±√3
{x>√3或x