1.2+2.3+3.4+...+n.(n+1)=(1/3)n(n+1)(n+2)& 1+2+3+…+n=(1/2)n(n+1) are true for all positive integers n.
Find the value of 1+(1+2)+(1+2+3)+…+(1+2+3+…+100)
收錄日期: 2021-04-25 17:19:14
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080113000051KK01891