请教寂静一题。多

刘民 · 发表于 2010-11-22 01:07:33

181

S: 假设有一个数列S(n),已知S(0),求S(n),
1) S(i) is i more than s(i-1) for any i>=1
2)the difference between S(i) and S(i-1) is i^2
条件一可求 S(i)=s(i-1)+i
条件二不可求无法确定是怎么样的数列
选A

I am not sure whether (2) tells us enough information to solve for S(n). Because (2) says: S(i) = S(i-1) + i^2, then, finally, we can solve s(i) from S(0). Did I miss anything here? Tons thanks.

efrenreyes · 发表于 2010-11-22 03:29:15

条件2：可能是S(i) = S(i-1) + i^2，也可能是S(i-1) = S(i) + i^2，故不充分。

fudanwyh · 发表于 2010-11-22 03:51:42

really tricky...

刘民 · 发表于 2010-11-22 04:25:51

Thanks a lot.

请教寂静一题。多

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