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分布问题

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APPSYZY Posted at 2021-4-10 11:18:57 |Read mode
Last edited by APPSYZY at 2021-4-10 11:32:00设$n\geqslant 2$为正整数,从区间$\left[ 0,1 \right] $随机取一实数记为$x_1$,然后从区间$\left[ 0,1-x_1 \right] $随机取一个实数记为$x_2$,然后从区间$\left[ 0,1-x_1-x_2 \right] $随机取一实数记为$x_3$……然后从区间$\left[ 0,1-x_1-x_2-\cdots -x_{n-2} \right] $随机取一实数记为$x_{n-1}$,最后记$x_n=1-x_1-x_2-\cdots -x_{n-1}$.求证:$\left( x_1,x_2,\cdots ,x_n \right) $均匀分散在空间$\left[ 0,1 \right] ^n$中.
注:区间$\left[ 0,0 \right] $可以视作集合$\left\{ 0 \right\} $.

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 Author| APPSYZY Posted at 2021-4-14 15:22:14
这个问题本身的描述也有点丑陋,应该还能改改

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色k Posted at 2021-4-14 15:26:32
n=2时,就是x2=1-x1吗?那(x1,x2)恒在线段上,这算均匀分散在[0,1]^2中?

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 Author| APPSYZY Posted at 2021-4-14 17:16:21
回复 3# 色k
这里均匀分散的意思就是指如果把题目描述的这个过程重复多次,得到多个点,当点足够多的时候,这些点均匀分布在空间里

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色k Posted at 2021-4-14 17:40:53
回复 4# APPSYZY

重复多少次它们都在y=1-x上啊,顶多是均匀分散在线段上,而不是[0,1]^2

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 Author| APPSYZY Posted at 2021-4-14 18:09:57
回复 5# 色k
的确,我最后的表述出错了。二位是均匀分布在线段$y=1-x,x\in \left[ 0,1 \right] $上,但是到了n维就不知道如何表述“均匀分布在XX”了...

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 Author| APPSYZY Posted at 2021-4-18 12:27:45
另外,其实我想证明的就是:给定n,当取很多个点的时候,这些点的第一个坐标$x_1$均匀分布在区间[0,1]中,第二个坐标$x_2$乃至第n个坐标$x_n$都均匀分布在区间[0,1]中。

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2025-4-21 01:40 GMT+8

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