题目内容：

化简求值(1/a+1-1/a-1)÷1/a-1,其中a=平方根2-1急

优质解答

(1/a+1-1/a-1)÷1/a-1
=(1/a+1-1/a-1)x(a-1)
=(a-1)/(a+1)-1
=(a-1-a-1)/(a+1)
=-2/(a+1)
=-2/(√2-1+1)
=-2/√2
=-√2