f(1)=0 x1--->f(x)=1/((x^2 1)/(x-1))=1/(x 1 2/(x-1))=1/((x-1) 2/(x-1) 2) x>1--->f(x)= xf(x)>=1/(-2sqrt(2) 2),x=1-sqrt(2)-->= 综合得,f(x)max=1/(2sqrt(2) 2),f(x)min=-1