鲁能巴蜀中学艺尖生:【一道数学题】5分钟解决

来源:百度文库 编辑:神马品牌网 时间:2024/05/06 10:01:56
先化简,再求值:4x/(x-1)÷[(x-1)/(x+1)-(x+1)/(x-1)],其中x=0
(过程)

原式=4X/(X-1)÷{(X^2+1-2X-X^2-1-2X)/[(X+1)(X-1)]}
=4X/(X-1)÷{-4X/[(X+1)(X-1)]}
=4X/(X-1)·(X+1)(X-1)/(-4x)
=-(X+1)
=-X-1
当x=0 时,原式=-1

此式无意义,当x等于0时,原式变为0/0

等于0