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If S is the sum of the reciprocals of the consecutive integers from 91 to 100, inclusive, which of the following is less than S?
I. 1/8
II. 1/9
III. 1/10
分析A选项
分析B选项
分析C选项
分析D选项
分析E选项
s=1/91+1/92+……+1/100 所以 10/100 <s<10/91 所以选c
刘易斯
这道题做的时候实在没有思路,局限在(1-1/2)+(1/2-1/3)...这个套路里了 实际上可以用不等式放缩一下 !!!10/100<1/91+...+1/100<10/91 所以大于1/10 小于1/9
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