先化简再求值(x^2/x-1-x+1)/4x^2-4x+1/1-x,其中x^2=1

问题描述:

先化简再求值(x^2/x-1-x+1)/4x^2-4x+1/1-x,其中x^2=1

=(x²-x²+x+x-1)/(x-1)×(1-x)/(2x-1)²
=(2x-1)/(x-1)×[-(x-1)/(2x-1)²]
=-1/(2x-1)
=1/(1-2x)