名校
1 . 一个车间有3台机床,它们各自独立工作,其中
型机床2台,
型机床1台.
型机床每天发生故障的概率为0.1,B型机床每天发生故障的概率为0.2.
(1)记X为每天发生故障的机床数,求
的分布列及期望
;
(2)规定:若某一天有2台或2台以上的机床发生故障,则这一天车间停工进行检修.求某一天在车间停工的条件下,B型机床发生故障的概率.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
(1)记X为每天发生故障的机床数,求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fc79c66ebaacd709ec9965b90a22b14.png)
(2)规定:若某一天有2台或2台以上的机床发生故障,则这一天车间停工进行检修.求某一天在车间停工的条件下,B型机床发生故障的概率.
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3卷引用:河南师范大学附属中学2024届高三下学期最后一卷数学试题
真题
2 . 已知集合
.给定数列
,和序列
,其中
,对数列
进行如下变换:将
的第
项均加1,其余项不变,得到的数列记作
;将
的第
项均加1,其余项不变,得到数列记作
;……;以此类推,得到
,简记为
.
(1)给定数列
和序列
,写出
;
(2)是否存在序列
,使得
为
,若存在,写出一个符合条件的
;若不存在,请说明理由;
(3)若数列
的各项均为正整数,且
为偶数,求证:“存在序列
,使得
的各项都相等”的充要条件为“
”.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0cd62e1c433cfb342fcd7f334ccc968f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1039be74acc3366c11fae59651f85d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f3fd26c26f6f07fabfa38eccf3d2fc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89441a335677dbf88779bbb65c543375.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dcedacb9353214d02e5f6c7e693ac7d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9353bc48a30bbf4d807d858c4604b1c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9353bc48a30bbf4d807d858c4604b1c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df6995fd4ede4b441f54a1e0996447ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6caacfd319814df87257a1823d8e801c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb7fbd87354b2529d4f0a155fad1b2cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62089081cbcb03a9495a3061b8570f60.png)
(1)给定数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52596c7a4a85221a0edb36591bd6a9e7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a4d9ec580a62b48148a48c711794a6f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62089081cbcb03a9495a3061b8570f60.png)
(2)是否存在序列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffa35373ec4e4684107b42adb7a5161.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62089081cbcb03a9495a3061b8570f60.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71d5d87042c71d41b61ee416d4f79724.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffa35373ec4e4684107b42adb7a5161.png)
(3)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6a766e037468d9c6e4bade3de283ae8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffa35373ec4e4684107b42adb7a5161.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62089081cbcb03a9495a3061b8570f60.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/666ba875a2642bbec1fdfcdab8e4e62d.png)
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3 . 进位制是人们为了计数和计算方便而约定的记数方式,通常“满二进一,就是二进制;满八进一,就是八进制;满十进一,就是十进制……;满几进一,就是几进制”.
我们研究的正整数通常是十进制的数,因此,将正整数
的各位上的数字分别记为
,则
表示为关于10的
次多项式,即
,其中
,
,记为
,简记为
.
随着计算机的蓬勃发展,表示整数除了运用十进制外,还常常运用二进制、八进制等等.更一般地,我们可类似给出
进制数定义.
进制数的定义:给出一个正整数
,可将任意一个正整数
,其各位上的数字分别记为
,则
唯一表示为下列形式:
,其中
,
,并简记为
.
进而,给出一个正整数
,可将小数
表示为下列形式:
,其中
,
,并简记为
.
(1)设
在三进制数下可以表示为
,
在十进制数下可以表示为
,试分别将
转化成十进制数,
转化成二进制数;
(2)已知数列
的前
项和为
,且满足
,
,数列
满足,当
时,
;
①当
时,求数列
的通项公式;
②证明:当
时,
.
我们研究的正整数通常是十进制的数,因此,将正整数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23dd0a10a73674c8a47420d7e91da0cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/432851e0d0b7a2924da29b9cc5ca1706.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05c95c671f517c02f1deccd2174f7465.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f856d17cdd7499eeea956845fe51ad2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ceec6993cc9e39a5d5e6097d6447c6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35d5a7b02c9d7bd9e2910849ab591fc9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/856f717993779ce676195ed3c8074e15.png)
随着计算机的蓬勃发展,表示整数除了运用十进制外,还常常运用二进制、八进制等等.更一般地,我们可类似给出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50e3273deabbf8c7d700d340b71ca2eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45c89fe2197a7044536c5c3b52789636.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3f285903ef04eb7a1d2071cb7197521.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c22a19eeff39dff098ea766cf74d3c69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53d2aae1ce527125960613e78e1bb501.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2a4ce3547aff6aebdd145d11c566fe.png)
进而,给出一个正整数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50e3273deabbf8c7d700d340b71ca2eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20277d6743703a3710d6ceb8dc869cef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31ef1766237596595c550af4600c370e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8e6d4140fcd9583fe03f91701ae083f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74304131e01d0e9e68bd8a566b30d529.png)
(1)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b104090ea2ac34be58a76a4e0e95cb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99dc317d03cfed7687fad0448c298f9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7df1d9b712b639c8b6809c9f3ae03706.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19d9abc918557b3bd56cb30dfd20b91f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b104090ea2ac34be58a76a4e0e95cb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7df1d9b712b639c8b6809c9f3ae03706.png)
(2)已知数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb451756eab7b736e0c576e03f6243b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f329b217e1051b23f0d61023cdc6e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/931b93e6ee1145e185621ae08dbf170f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26663935b7cb86ca81ad2aa73d49e26a.png)
①当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/931b93e6ee1145e185621ae08dbf170f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f329b217e1051b23f0d61023cdc6e69.png)
②证明:当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/931b93e6ee1145e185621ae08dbf170f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac363332016ae0fa59a5e4a1d41e2a0b.png)
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名校
解题方法
4 . 为了选拔雏鹰计划的预备人员,某地区教育局对高一年级新生进行了测试(测试分为初试和复试).现共有400名学生参加初试,且所有学生的初试成绩
近似服从正态分布
,根据以往入选同学的初试和复试成绩走势,本届复试作出如下规定:①初试成绩高于91分者免于复试,直接确定为雏鹰计划的预备人员;②初试成绩高于80分且不超过91分的学生有资格参加复试,下图为从以往入围雏鹰计划预备人员的所有同学中随机抽取的20名同学的的初试和复试成绩.
(2)复试试题由两道数学题和两道物理题构成,已知数学题的难度系数为0.5(可以理解为进入复试的学生答对每道数学题目的概率是0.5),物理题目的难度系数均为
,能否答对这些题目相互独立,每个考生需答完四个题目,至少答出其中三个即通过复试并确定为雏鹰计划的预备人员,如果本次确定为雏鹰计划的预备人员数目不能超过33人,请确定物理试题的难度系数
的取值范围.
附:若随机变量
服从正态分布
,则
,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0210a70d3664db67006ecd0cbc88e864.png)
(2)复试试题由两道数学题和两道物理题构成,已知数学题的难度系数为0.5(可以理解为进入复试的学生答对每道数学题目的概率是0.5),物理题目的难度系数均为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
附:若随机变量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdfc26b8bdcd1fd3781c4593217c725e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04398619f7b3251b93fb34cc14930f8d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14360db70f4872cf5b47f12090fc211b.png)
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解题方法
5 . 已知在
中,
的面积为
.
的度数;
(2)若
是
上的动点,且
始终等于
,记
.当
取到最小值时,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8d80664a665cbdff97f0c2c47541d71.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12c3a75358a870c58549cf88b82fcc18.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1384d0a02d097ac7aa8a19e8da6f9767.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6b86c22b670a8e9f3896f9e8883fbbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d4538fa852e0f4961d442e9d5b96a69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
您最近一年使用:0次
名校
6 . 水平相当的甲、乙、丙三人进行乒乓球擂台赛,每轮比赛都采用3局2胜制(即先贏2局者胜),首轮由甲乙两人开始,丙轮空;第二轮由首轮的胜者与丙之间进行,首轮的负者轮空,依照这样的规则无限地继续下去.
(1)求甲在第三轮获胜的条件下,第二轮也获胜的概率;
(2)求第
轮比赛甲轮空的概率;
(3)按照以上规则,求前六轮比赛中甲获胜局数的期望.
(1)求甲在第三轮获胜的条件下,第二轮也获胜的概率;
(2)求第
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
(3)按照以上规则,求前六轮比赛中甲获胜局数的期望.
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7日内更新
|
583次组卷
|
3卷引用:辽宁省大连市部分学校2024届高三下学期联合模拟考试数学试题
辽宁省大连市部分学校2024届高三下学期联合模拟考试数学试题浙江省北斗星盟2023-2024学年高二下学期5月阶段性联考数学试题(已下线)专题06 离散型随机变量与正态分布--高二期末考点大串讲(苏教版2019选择性必修第二册)
解题方法
7 . 将足够多的一批规格相同、质地均匀的长方体薄铁块叠放于水平桌面上,每个铁块总比其下层铁块向外伸出一定的长度,如下图,那么最上层的铁块最多可向桌缘外伸出多远而不掉下呢?这就是著名的“里拉斜塔”问题.将铁块从上往下依次标记为第1块、第2块、第3块、……、第n块,将前
块铁块视为整体,若这部分的重心在第
块的上方,且全部铁块整体的重心在桌面的上方,整批铁块就保持不倒.设这批铁块的长度均为1,若记第n块比第
块向桌缘外多伸出的部分的最大长度为
,则根据力学原理,可得
,且
为等差数列.
的通项公式;
(2)记数列
的前
项和为
.
①比较
与
的大小;
②对于无穷数列
,如果存在常数
,对任意的正数
,总存在正整数
,使得
,
,则称数列
收敛于
,也称数列
的极限为
,记为
;反之,则称
不收敛.请根据数列收敛的定义判断
是否收敛?并据此回答“里拉斜塔”问题.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c5abd5f2fc2744d7f706656575b7262.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12444d6e8d3b097a9d090e6ed06042e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a0876215b2fd463d151523cd3c6b447.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ee45219629dd30af171588e646f8b12.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7b78e4a03d4595f14be42054b61dfc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
(2)记数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
①比较
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c6b6c6934eda8f0838d0ba881be2211.png)
②对于无穷数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1fd18a909cecbaee7115d6b15631d83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/711c92626a97e6b778b3aa86e663ee97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4ccd4537f4dee2050ade38b972eb9b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74d1d3b9d14068d68a7cff35ce3e872c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f4691ee07234d7cfc8a21bed1236c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1fd18a909cecbaee7115d6b15631d83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1fd18a909cecbaee7115d6b15631d83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b85738365edd32d8df21b2d36518029.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1fd18a909cecbaee7115d6b15631d83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d013861990cf331c82eb453416ae31bc.png)
您最近一年使用:0次
解题方法
8 . 如图所示的几何体是由圆锥
与圆柱
组成的组合体,其中圆柱的轴截面
是边长为2的正方形,圆锥的高
,M为圆柱下底面圆周上异于A,B的点.
∥平面
;
(2)若
,求直线
与平面
所成角的正切值的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41a8c34f622f1b979feed5ae6ae5d0e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae0a4f38420bb9215dbc9c875b755838.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a55a6b8045f2d6429ac49997c1124a25.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/defa5b53043ae802bb1af7d14374406d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08452588675f76da2f8d31387b3a8224.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b10c2bc31ab83c89237b93159ae64c1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08452588675f76da2f8d31387b3a8224.png)
您最近一年使用:0次
解题方法
9 . 已知函数
的图象与
轴交于点
,且在
处的切线方程为
,记
.(参考数据:
).
(1)求
的解析式;
(2)求
的单调区间和最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc05f752a777614011647451889874cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a87dbf8a0849b60206932ca8e8401af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b2b2f10a84d9700f906e4f8f74b0817.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b7843538ce5376655b5d4f269798af5.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/028517e8bebe634441e0a5c79828e88a.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18c49ca8562b98657ca9c499093f7233.png)
您最近一年使用:0次
解题方法
10 . 已知
两个盒子中各有一个黑球,一个白球.每次从两个盒子中各随机取出一个小球交换后放回.记
次交换后,
盒子中有一黑一白两个小球的概率为
盒子中黑球的个数为
.
(1)求
;
(2)求
的数学期望
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01c74a907dda6bb7d9d56d009d9df253.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f78093af1942339f74a1ec6e99aaab4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93d0f3799612b81e85b87241ec8eee68.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf83e20035c3afd6d26ebfd53d768a70.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93d0f3799612b81e85b87241ec8eee68.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6522c8c52be9ae43994b0cfccaa887f.png)
您最近一年使用:0次