题目;1-1/10-1/100-1/1000-……-1/10000000000

问题描述:

题目;1-1/10-1/100-1/1000-……-1/10000000000

因为1/10+1/100+...+1/[10^{10}]=[1/10-1/10^{11}]/[1-1/10]=1/9-1/(9*10^{10}
所以1-1/10-1/100-1/1000-……-1/10000000000
=1-1/9+1/(9*10^{10}
=80000000001/90000000000
(分子中有9个零,分母中有10个零)

1-1/10-1/100-1/1000-……-1/10000000000
=1-(0.1+0.01+0.01+……+0.000 000 0001)
=1-0.111 111 1111
=0.888 888 8889

=1-(0.1+0.01+...+0.0000000001)
=1-0.1111111111
=0.8888888889