y=根号下log10(x^2-x-1)的定义域是
log10(x^2-x-1)>=0
真数:x^2-x-1>0
log10(x^2-x-1)>=0
x^2-x-1>=1
(x-2)(x+1)>=0
x>=2,x0
(x-1/2)^2>5/4
x>1/2+根号5/2,X