22-23高三上·江苏盐城·阶段练习
名校
解题方法
1 . 为了研究某单链RNA病毒,科学家先对该病毒的RNA进行分析,得知其中碱基
约占
,碱基
约占
,碱基
约占
,碱基
约占
.现科学家欲人工模拟合成一条RNA,采用的原料按照原病毒RNA各碱基之比混合而成,原料中每个碱基片段连接到合成RNA上的概率相等,合成的RNA上连续出现两个
时即停止合成.
(1)计算合成RNA仅有4个碱基的概率,并计算27次重复实验下,仅有4个碱基的数学期望
(2)求合成RNA的碱基数量的数学期望.
(提示:当
充分大时,对于某一绝对值小于
的常数
,认为有
)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f1dd362f843e640ce551ad1787c9873.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9af46237d7279ffb682d57e4e7b57a2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b624e6d456c5aa077dfd00ada3a311d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b52b4f24969673c863b5aff4fb6751ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9af46237d7279ffb682d57e4e7b57a2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
(1)计算合成RNA仅有4个碱基的概率,并计算27次重复实验下,仅有4个碱基的数学期望
(2)求合成RNA的碱基数量的数学期望.
(提示:当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9526c32a3859acb8b0ec57f72ef2afec.png)
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