求級數和:
1.sigma(k=1~n)k(k+1)(k+2)
2.數列an滿足an+1=an+4n^2,n>=1且a1=1
試求數列an通式(ans:1/3(4n^3-6n^2+2n+3)
3.一數列an滿足a1+2a2+...+nan=n^2+3n+1,n>=1
則a100值為?(ans:101/50)
數列an的通式為?
THANKS!!
收錄日期: 2021-05-01 09:35:48
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20150318000015KK03388