Find sum to n terms of :
1 x 2 + 2 x 5 + 3 x 8 + 4 x 11 + ...... + n ( 3n - 1)
in terms of n.
Summation
2013-06-16 1:25 am
回答 (1)
2013-06-16 2:28 am
✔ 最佳答案
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2013-06-15 21:18:08 補充：
You can try to prove this by M.I.
Another method, for your reference:
http://hk.knowledge.yahoo.com/question/article?qid=6912021400443
參考: My Maths World
收錄日期: 2021-04-13 19:30:47
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20130615000051KK00260