当x=根号3时,代数式(x-1分之x - x+1分之x)÷ 1-x分之2x的值是
问题描述：
当x=根号3时,代数式(x-1分之x - x+1分之x)÷ 1-x分之2x的值是
答
=x[1/(x-1)-1/(x+1)]×[-(x-1)/2x]
=x(x+1-x-1)/(x-1)(x+1)×[-(x-1)/2x]
=-1/(x+1)
当x=√3时
原式=-1/(√3+1)
=-(√3-1)/2