证法一：设x=0.9999999999999999999999999999…… 两边同时乘以10得 10x=9.999999999999999999999999999……=9+x 故10x=9+x从而x=1 证法二：设x=0.9999999999999999999999999999…… =0.9+0.09+0.009+0.0009+…… 形...
