06/11/05 10:25:14
0.1+0.9=(1ー0.9)+0.9
0.01+0.99=(1ー0.99)+0.99
0.001+0.999=(1ー0.999)+0.999
0.0001+0.9999=(1ー0.9999)+0.9999
0.000…1+0.999…9=(1ー0.999…9)+0.999…9
lim[m→∞]
{Π[n=1~m]0.1
+∑[n=1~m](9*0.1^n)}
=lim[m→∞]{0.1^m
+∑[n=1~m](9*0.1^n)}
・ ・
=(1ー0.9)+0.9
=1