1 . 有一个猜谜语活动,有A和B两道谜语,小明猜对A谜语的概率为0.8,猜对获得奖金10元,猜对B谜语的概率为0.5,猜对获得奖金20元.猜不出不给奖金.
(1)设事件A:“两道谜语中小明恰好答对一道”,求
;
(2)如果按照规则猜谜:只有在猜对一道谜语的情况下,才有资格猜下一道.
(i)如果猜谜语顺序由小明选择,小明应该先猜哪一道呢?
(ii)若小明已经获得30元奖金,此时主办方临时增加了一道终极谜语C,参赛者可以自行选择是否继续猜谜.假设小明猜对C谜语的概率为a,若小明不继续,可以直接拿走奖金,若继续且答错C谜语,则没收全部奖金.若继续且答对C谜语,即可获得奖金90元.问:概率a至少为何值,值得小明同学继续猜谜?
(1)设事件A:“两道谜语中小明恰好答对一道”,求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27b6f8cb2faaad82b53b2a66ee817a37.png)
(2)如果按照规则猜谜:只有在猜对一道谜语的情况下,才有资格猜下一道.
(i)如果猜谜语顺序由小明选择,小明应该先猜哪一道呢?
(ii)若小明已经获得30元奖金,此时主办方临时增加了一道终极谜语C,参赛者可以自行选择是否继续猜谜.假设小明猜对C谜语的概率为a,若小明不继续,可以直接拿走奖金,若继续且答错C谜语,则没收全部奖金.若继续且答对C谜语,即可获得奖金90元.问:概率a至少为何值,值得小明同学继续猜谜?
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2 . 在直线l上任取不同的两点A,B,称
为直线l的方向向量与直线l的方向向量垂直的非零向量称为l的法向量,在平面直角坐标系中,已知直线
是函数
的图象,直线
是函数
的图象.
(1)求直线
和直线
所夹成的锐角的余弦值;
(2)已知直线
平分直线
与直线
所夹成的锐角,求直线
的一个方向向量的坐标;
(3)已知点
,A是
与y轴的交点,
是
的法向量.求
在
上的投影向量的坐标(求出一个即可),并求点P到直线
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9795e7f5cb9b366776c41d8f3f43942.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e9b0f5f44abbc6544a2f672b025b013.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c30fd97fafb3779aa4f4660f41e2939.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f6f17bc385bafb37e8f964e5eb99cd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/549bc1c85c955e6511fff0a81b6adc39.png)
(1)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e9b0f5f44abbc6544a2f672b025b013.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f6f17bc385bafb37e8f964e5eb99cd0.png)
(2)已知直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9fce9427c9b17e4d3cda0c3ff3e2e14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e9b0f5f44abbc6544a2f672b025b013.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f6f17bc385bafb37e8f964e5eb99cd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9fce9427c9b17e4d3cda0c3ff3e2e14.png)
(3)已知点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d658b3385c5aa6be7e66f636648af14b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e9b0f5f44abbc6544a2f672b025b013.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1b8a88a16125366536cb4ad658e0cf1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e9b0f5f44abbc6544a2f672b025b013.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68f654198c1e01d97f1378b35d7c68ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1b8a88a16125366536cb4ad658e0cf1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e9b0f5f44abbc6544a2f672b025b013.png)
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3 . 对于给定的一个
位自然数
(其中
,
),称集合
为自然数
的子列集合,定义如下:
{
且
,使得
},比如:当
时,
.
(1)当
时,写出集合
;
(2)有限集合
的元素个数称为集合
的基数,一般用符号
来表示.
(ⅰ)已知
,试比较
大小关系;
(ⅱ)记函数
(其中
为
这
个数的一种顺序变换),并将能使
取到最小值的
记为
.当
时,求
的最小值,并写出所有满足条件的
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6be3d8ff4885ce8cf21ed3b7e4c9059.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff4ab89a62749697c6a67e4fe8e6f3c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12b0e3b00fe47801afb53ec56706c21a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5123cae73867329882792f626287b970.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d688a7cacda715fc5c2fad9a2adaddee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab691edda624f588e85d493423b3e398.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76fb6d4810762396e3fbe728687a0794.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba7a9e06bedb3aca590121cc47e64e52.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e534ff8ca5451dce6629223e002d5878.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d407ed5fd8a5fd413426fc1fc118422.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eeaa1b4ec60977b69d48d3d023f5d731.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5123cae73867329882792f626287b970.png)
(2)有限集合
![](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/cc8279d9dd0b7750953cb9e2098b3b90.png)
(ⅰ)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b43ea4161df6e6178c26c524935af465.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b53fe2a5d83d2e3e97f3a49d1f845370.png)
(ⅱ)记函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a2a7d5abc0e14bf1da403fba5b27644.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c558c7204d256c96b74b9c991c0e5c1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/086eb439f6a1578fdba904825340772d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aad1bf0868f56ad3bda73d4ca5851cb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbf91726683a3963e941231877c8c6ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e731e11a03c0f5d2768e87a3442634d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c326b4a68d5148e8e5a5ebc15d3b132.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aad1bf0868f56ad3bda73d4ca5851cb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e731e11a03c0f5d2768e87a3442634d.png)
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