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who can solve this?
[版面:窗口里的风景][首篇作者:leonxf] , 2003年10月10日04:04:22 ,560次阅读,2次回复
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leonxf
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发信人: leonxf (leonxf), 信区: DotNet
标  题: who can solve this?
发信站: Unknown Space - 未名空间 (Fri Oct 10 04:04:22 2003) WWW-POST

Suppose C(m,n) means m!/(m-n!)n!, can anyone simplify the following
expression, no matter by hand or by Maple or something?

Sum(f(k),k=1,2,...,n), where
f(k)=Sum[C(2k-1+j,k-1)C(m+n-2k-j,m-k),j=0,1,...,(n-k)]/mC(m+n,n)

What I already know is when m=n, the answer is just 1/2, for any m or n.

If anyone has a clue, please email me at [email protected] I really appreciate
your help!


--
※ 来源:.Unknown Space - 未名空间 mitbbs.com.[FROM: 24.126.]

 
st
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发信人: st (月光下老虎慢慢吃人), 信区: DotNet
标  题: Re: who can solve this?
发信站: Unknown Space - 未名空间 (Fri Oct 10 11:03:37 2003), 站内信件

your home? and it has nothing to do with .net?
【 在 leonxf (leonxf) 的大作中提到: 】
: Suppose C(m,n) means m!/(m-n!)n!, can anyone simplify the following
: expression, no matter by hand or by Maple or something?
: Sum(f(k),k=1,2,...,n), where
: f(k)=Sum[C(2k-1+j,k-1)C(m+n-2k-j,m-k),j=0,1,...,(n-k)]/mC(m+n,n)
: What I already know is when m=n, the answer is just 1/2, for any m or n.
: If anyone has a clue, please email me at [email protected] I really appreciate
: your help!


--
一只小老虎慢慢的走了过来。红着脸,问小松鼠说,“请问。。。我可以吃你吗?”
小松鼠觉得这个问法蛮好玩的,说“你是第一次吃动物吗?”小老虎更不好意思了,说,
“是的。。。妈妈不在家了。。。”“那。。你以前吃什么呢?”小松鼠又好奇的问到。
“……”“什么?说大声点。。。我听不到”“吃奶!”说完,小老虎的脸更红更红了。
--[转载]月光下老虎慢慢吃人

※ 来源:.Unknown Space - 未名空间 mitbbs.com.[FROM: 204.71.]

 
leonxf
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发信人: leonxf (leonxf), 信区: DotNet
标  题: Re: who can solve this?
发信站: Unknown Space - 未名空间 (Fri Oct 10 20:38:32 2003) WWW-POST

This is something I get from Economics.

【 在 st (月光下老虎慢慢吃人) 的大作中提到: 】
: your home? and it has nothing to do with .net?
: 【 在 leonxf (leonxf) 的大作中提到: 】
: : Suppose C(m,n) means m!/(m-n!)n!, can anyone simplify the following
: : expression, no matter by hand or by Maple or something?
: : Sum(f(k),k=1,2,...,n), where
: : f(k)=Sum[C(2k-1+j,k-1)C(m+n-2k-j,m-k),j=0,1,...,(n-k)]/mC(m+n,n)
: : What I already know is when m=n, the answer is just 1/2, for any m or n.
: : If anyone has a clue, please email me at [email protected] I really
appreciate
: : your help!
:
:


--
※ 来源:.Unknown Space - 未名空间 mitbbs.com.[FROM: 128.97.]

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