题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090134-93699.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090134-16773.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090134-91551.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090134-87277.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090134-66514.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090134-81139.png)
(1)若出现
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090134-16773.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090134-87277.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090135-46121.png)
(2)求
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090134-81139.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090135-46121.png)
(3)若出现恰好两棵树成活的的概率最大,试求
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090135-46121.png)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090135-52834.png)
(2)
![]() | 0 | 1 | 2 | 3 | 4 |
P | ![]() | ![]() | ![]() | ![]() | ![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090136-63908.png)
解析
解:(1)由题意,得
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090136-42876.png)
(2)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090135-11566.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090136-74041.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090137-44256.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090137-88346.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090137-63309.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090137-32413.png)
得
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090135-11566.png)
![]() | 0 | 1 | 2 | 3 | 4 |
P | ![]() | ![]() | ![]() | ![]() | ![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090135-40515.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090135-73265.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090136-95230.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090136-19491.png)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090137-29576.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090135-73265.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090135-11736.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090137-29576.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090136-19491.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090135-11736.png)
由上述不等式解得a的取值范围是
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090136-63908.png)
核心考点
试题【在我市“城乡清洁工程”建设活动中,社会各界掀起净化美化环境的热潮.某单位计划在小区内种植四棵风景树,受本地地理环境的影响,两棵树的成活的概率均为,另外两棵树为进】;主要考察你对离散型随机变量及其分布列等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090127-81006.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090127-51829.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090128-42328.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090128-29348.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090122-58104.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090122-62510.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090122-59897.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090122-71974.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090123-71371.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090108-51039.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090108-47978.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090109-71745.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090109-10746.png)
(Ⅰ)试用
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090108-51039.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090109-67590.png)
(Ⅱ)记从口袋中三次摸奖(每次摸奖后放回)恰有一次中奖的概率为
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090109-37462.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090109-37462.png)
(Ⅲ)在(Ⅱ)的条件下,将
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090109-10746.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090108-51039.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090109-49647.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090109-49647.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090109-65691.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090110-62573.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090110-98807.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090110-98807.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090103-98065.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191027/20191027090103-23638.png)