summation??
回答 (2)
2007-05-30 3:32 am
✔ 最佳答案
=1X2+2X3+3X4+4X5=(公式)4X5X6/3
=40
2007-05-29 7:45 pm
f S(n)=(n,summation,r=1) , r(r+1),
S(4) = 1(1+1) + 2(2+1) + 3(3+1) + 4(4+1)
= 3 + 6 + 12 + 20
= 41
S(4) = 1(1+1) + 2(2+1) + 3(3+1) + 4(4+1)
= 3 + 6 + 12 + 20
= 41
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原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070529000051KK01079