两种方法:(一)分离常数法;(二)反函数法.
(法一)原来函数变形:y=(2x-1)/(x-1)=(2x-2+1)/(x-1)
=[2(x-1)+1]/(x-1)=2+1/(x-1)
因为x>0,所以(x-1)>-1
则:当(x-1)>0时,1/(x-1)>0,所以2+1/(x-1)>2,即y>2
当-1
两种方法:(一)分离常数法;(二)反函数法.
(法一)原来函数变形:y=(2x-1)/(x-1)=(2x-2+1)/(x-1)
=[2(x-1)+1]/(x-1)=2+1/(x-1)
因为x>0,所以(x-1)>-1
则:当(x-1)>0时,1/(x-1)>0,所以2+1/(x-1)>2,即y>2
当-1