1 . 设
(
,
).
(1)若展开式中第5项与第7项的系数之比为3∶8,求k的值;
(2)设
(
),且各项系数
,
,
,…,
互不相同.现把这
个不同系数随机排成一个三角形数阵:第1列1个数,第2列2个数,…,第n列n个数.设
是第i列中的最小数,其中
,且i,
.记
的概率为
.求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40e015379cb6580f4412dcf1fdfdc3ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c972cbd63decec197aec1bdc306de67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46b6d151d3f864bae873987f6db9327a.png)
(1)若展开式中第5项与第7项的系数之比为3∶8,求k的值;
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3dbc79bfe1e18890b15a0f211b3da6dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36b98ef143f8159f3a7dafa1fd2f2370.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f35f7dcce39f3d4dc6b7faf84dc1d0a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f255d0395fba51ca2d44293cca42e0a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b00f4eb7f1bd2ccefbabf0c1dfa8f69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e90c998886b1483221a5b4941f6e874c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ef835c9ad2636a9662fb6c99e3abc78.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36b98ef143f8159f3a7dafa1fd2f2370.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b300326e522dc458655079b5dcd0a05f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf83e20035c3afd6d26ebfd53d768a70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d02d6bfc8f3e1c661ba2732a00a6352.png)
您最近一年使用:0次
2020-07-15更新
|
1427次组卷
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4卷引用:江苏省南通市2020届高三下学期第四次调研测试数学试题
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2 . 口袋中有大小、形状、质地相同的两个白球和三个黑球.现有一抽奖游戏规则如下:抽奖者每次有放回的从口袋中随机取出一个球,最多取球2n+1(n
)次.若取出白球的累计次数达到n+1时,则终止取球且获奖,其它情况均不获奖.记获奖概率为
.
(1)求
;
(2)证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bec1b383f61d7a71f10ce999c9321381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf83e20035c3afd6d26ebfd53d768a70.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2708fa6298e52f617383efc175b71ddc.png)
(2)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18adc4ec9010e1e99b882761e9c2c2e.png)
您最近一年使用:0次
2020-06-05更新
|
1873次组卷
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江苏省南京市2020届高三下学期6月第三次模拟考试数学试题(已下线)专题10-2 概率压轴大题(理)-2022年高考数学毕业班二轮热点题型归纳与变式演练(全国通用)湖北省九校教研协作体2022-2023学年高二上学期9月联考数学试题(已下线)4.1.3独立性与条件概率的关系(2)