名校
1 . 随着现代电子技术的迅猛发展,关于元件和系统可靠性的研究已发展成为一门新的学科——可靠性理论.在可靠性理论中,一个元件正常工作的概率称为该元件的可靠性.元件组成系统,系统正常工作的概率称为该系统的可靠性.现有
(
,
)种电子元件,每种2个,每个元件的可靠性均为
(
).当某元件不能正常工作时,该元件在电路中将形成断路.现要用这
个元件组成一个电路系统,有如下两种连接方案可供选择,当且仅当从A到B的电路为通路状态时,系统正常工作.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/29/7e8acff6-dd73-49e5-b7a2-13d3593082f8.png?resizew=393)
(1)(i)分别写出按方案①和方案②建立的电路系统的可靠性
、
(用
和
表示);
(ii)比较
与
的大小,说明哪种连接方案更稳定可靠;
(2)设
,
,已知按方案②建立的电路系统可以正常工作,记此时系统中损坏的元件个数为
,求随机变量
的分布列和数学期望.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cea4ac187cbb465180e89f38250b3970.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0704f453b2de48d36911f7db496bbf82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20c11f6c800b8e0410674a0c6d307d26.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d51f9147b8265c0276c1f2c2659197.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/29/7e8acff6-dd73-49e5-b7a2-13d3593082f8.png?resizew=393)
(1)(i)分别写出按方案①和方案②建立的电路系统的可靠性
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2708fa6298e52f617383efc175b71ddc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b9cb8e6ff801523b0304576cd69fd2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
(ii)比较
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2708fa6298e52f617383efc175b71ddc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b9cb8e6ff801523b0304576cd69fd2d.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fac3649308b528fd56545ba102dc42d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/949ab4f3efd2d63a97688c21098a7a20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
您最近一年使用:0次
2020-06-17更新
|
920次组卷
|
2卷引用:吉林省东北师范大学附属中学2020届高三第四次模拟考试数学(理)试题
解题方法
2 . 树人中学某班同学看到有关产品抽检的资料后,自己设计了一个模拟抽检方案的摸球实验.在一个不透明的箱子中放入10个小球代表从一批产品中抽取出的样本(小球除颜色外均相同),其中有
个红球(
,
),代表合格品,其余为黑球,代表不合格品,从箱中逐一摸出
个小球,方案一为不放回摸取,方案二为放回后再摸下一个,规定:若摸出的
个小球中有黑色球,则该批产品未通过抽检.
(1)若采用方案一,
,
,求该批产品未通过抽检的概率;
(2)(ⅰ)若
,试比较方案一和方案二,哪个方案使得该批产品通过抽检的概率大?并判断通过抽检的概率能否大于
?并说明理由.
(ⅱ)若
,
,现采用(ⅰ)中概率最大的方案,设在一次实验中抽得的红球为
个,求
的分布列及数学期望.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9952125a947b88e068d9d7a54583a7d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c38f3baf9a34265fbdb5c65dd1664d6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
(1)若采用方案一,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43c7630484d76b37662fe1c4ebdf2f9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e94f16d5ed858699bfea5039a7bf8ae6.png)
(2)(ⅰ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8a3cc8c48bf54ec8252e5dce6867754.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24c4bf61e073c899494b2fb3b767b108.png)
(ⅱ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43c7630484d76b37662fe1c4ebdf2f9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8a3cc8c48bf54ec8252e5dce6867754.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
您最近一年使用:0次