maths
回答 (2)
2009-12-21 8:36 pm
✔ 最佳答案
1/1x2+1/2x3+......+1/99x100=(1/1-1/2)+(1/2-1/3)+......+(1/99-1/100)
=1/1-1/100
=99/100
參考: me
2009-12-21 1:18 am
Σ 1/n(n+1) [from 1 to 99]
=Σ [1/n-1/(n+1)] [from 1 to 99]
=(1/1-1/2)+(1/2-1/3)+...+(1/99-1/100)
=1/1-1/100
=99/100
=Σ [1/n-1/(n+1)] [from 1 to 99]
=(1/1-1/2)+(1/2-1/3)+...+(1/99-1/100)
=1/1-1/100
=99/100
收錄日期: 2021-04-13 16:59:29
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20091220000051KK00954