计算(1/x+1 -1/1-x^2)除以3x/x+1

问题描述:

计算(1/x+1 -1/1-x^2)除以3x/x+1

=[1/(x+1)+1/(x+1)(x-1)]×(x+1)/3x
=x/(x+1)×(x+1)/3x
=1/3