名校
解题方法
1 . 若
,
是样本空间
上的两个离散型随机变量,则称
是
上的二维离散型随机变量或二维随机向量.设
的一切可能取值为
,
,记
表示
在
中出现的概率,其中
.
(1)将三个相同的小球等可能地放入编号为1,2,3的三个盒子中,记1号盒子中的小球个数为
,2号盒子中的小球个数为
,则
是一个二维随机变量.
①写出该二维离散型随机变量
的所有可能取值;
②若
是①中的值,求
(结果用
,
表示);
(2)
称为二维离散型随机变量
关于
的边缘分布律或边际分布律,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5c1116ce7f5a1a7b57517276d5092fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffa35373ec4e4684107b42adb7a5161.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4d15d2e2dc5b64da00f2f90613f6b73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffa35373ec4e4684107b42adb7a5161.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4d15d2e2dc5b64da00f2f90613f6b73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fadab9bb02100d7e9f12989b89721482.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66ae8920473eb5e860b0d625d0fe07eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8038ba89dea0aa5c0e760bb5ed5f8561.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fadab9bb02100d7e9f12989b89721482.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffa35373ec4e4684107b42adb7a5161.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00e2fc8dcdb957351e81bd926db46ef9.png)
(1)将三个相同的小球等可能地放入编号为1,2,3的三个盒子中,记1号盒子中的小球个数为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5c1116ce7f5a1a7b57517276d5092fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4d15d2e2dc5b64da00f2f90613f6b73.png)
①写出该二维离散型随机变量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4d15d2e2dc5b64da00f2f90613f6b73.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a64d924836b4292239d9726c6473d7f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a061d6375056092d2d831bd7cae6988.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fbefad0c67ac64be204e45c95b2dc35.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4d15d2e2dc5b64da00f2f90613f6b73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbe4cecc21cb09b200a771b8ec5cea0f.png)
您最近一年使用:0次
2024-03-29更新
|
2032次组卷
|
4卷引用:2024届山东省滨州市一模联考数学试题
解题方法
2 . 在正四棱锥
中,
,
,过侧棱
的延长线上一点
作与平面
平行的平面,分别与侧棱
,
,
的延长线交于点
,
,
.设几何体
和几何体
的外接球半径分别为
和
,当
最小时,
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cedd51383f8f047f565191b128cec637.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eeebacd7456b6471fd185e4cb8356a2a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97c01fdc7bc471af0b264a04aef0823e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6795cae2df43a722e1355e9562d93c09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/724625d4f91f0e48712d6d143a6389b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9efc18a5bb2e53586331b2a58538a48b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19f20f21a9d50b61dac519a3ddab539d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/957893cf7210e66bd614e9e00dc9ff5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b09fed6ffd4867550ea35301ca3acdf.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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3 . 设双曲线
的焦距为
,离心率为
,且
成等比数列,A是
的一个顶点,
是与A不在
轴同侧的焦点,
是
的虚轴的一个端点,
为
的任意一条不过原点且斜率为
的弦,
为
中点,
为坐标原点,则下列判断错误的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ef66f4832adc43902055a7e6d258037.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8dcc91c2ffb5571eaf944c34f5e8ffe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/168b3e4b1d6f04226fa2687a72a268b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eac0b1cedb503907f2ccf9bee9698f0d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2799abb64fd7bfce9dfa7228aa460564.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
A.![]() ![]() |
B.![]() |
C.![]() ![]() ![]() |
D.若![]() ![]() |
您最近一年使用:0次
2023-03-26更新
|
1049次组卷
|
7卷引用:山东省滨州市邹平市第二中学2023年高三下学期3月月考数学试题
2023·全国·模拟预测
解题方法
4 . 如图所示的六面体由两个棱长为a的正四面体
,
组合而成,记正四面体
的内切球为球
,正四面体
的内切球为球
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/821f0d613798f996ec62f8744a9238e9.png)
______ ;若在该六面体内放置一个球O,则球O的体积的最大值是______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5d90f940f5693b22ddf2e7c761887d8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7edc2e23df190c35aafad93410a05b8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5d90f940f5693b22ddf2e7c761887d8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f919bd3dde10dbbc076f7ec5149699.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7edc2e23df190c35aafad93410a05b8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c4f6f74444b2b7947fc6e35c8d62322.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/821f0d613798f996ec62f8744a9238e9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/20/f42eea31-b9ca-4d37-bef6-02478910aa64.png?resizew=134)
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名校
解题方法
5 . 如图所示,一个平面内任意两两相交但不重合的若干条直线,直线的条数与这些直线将平面所划分的区域个数满足如下关系:1条直线至多可划分的平面区域个数为2;2条直线至多可划分的平面区域个数为
;3条直线至多可划分的平面区域个数为7;4条直线至多可划分的平面区域个数为11;一般的,
条直线至多可划分的平面区域个数为__________ ;在一个平面内,对于任意两两相交但不重合的若干个圆,类比上述研究过程,可归纳出:
个圆至多可划分的平面区域个数为__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f1d8cb672db61735be7cbcd3d50bf9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/28/0aac4101-3a0d-428a-a18f-5705c7eb7166.png?resizew=511)
您最近一年使用:0次
2023-02-04更新
|
512次组卷
|
3卷引用:山东省滨州市滨城区北镇中学2023届高三下学期3月质量检测模拟数学试题
山东省滨州市滨城区北镇中学2023届高三下学期3月质量检测模拟数学试题山西省运城市稷山县稷山中学2022-2023学年高三上学期12月月考数学试题(已下线)专题10 数列通项公式的求法 微点2 累加法
2021·全国·模拟预测
6 . 在一张纸片上,画有一个半径为4的圆(圆心为M)和一个定点N,且
,若在圆上任取一点A,将纸片折叠使得A与N重合,得到折痕BC,直线BC与直线AM交于点P.
![](https://img.xkw.com/dksih/QBM/2021/12/29/2882961589714944/2883222960324608/STEM/7bc185cb144f43e899e51fdb9de8dada.png?resizew=161)
(1)若以MN所在直线为
轴,MN的垂直平分线为x轴,建立如图所示的平面直角坐标系,求点P的轨迹方程;
(2)在(1)中点P的轨迹上任取一点D,以D点为切点作点P的轨迹的切线
,分别交直线
,
于S,T两点,求证:
的面积为定值,并求出该定值;
(3)在(1)基础上,在直线
,
上分别取点G,Q,当G,Q分别位于第一、二象限时,若
,
,求
面积的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72811997a9f65e01fcc1d318bbd4d0dc.png)
![](https://img.xkw.com/dksih/QBM/2021/12/29/2882961589714944/2883222960324608/STEM/7bc185cb144f43e899e51fdb9de8dada.png?resizew=161)
(1)若以MN所在直线为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
(2)在(1)中点P的轨迹上任取一点D,以D点为切点作点P的轨迹的切线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08b9f0b9e53a83e68f5fec944f343119.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4407788e4dc88210bca71a2551d4f2f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/648dad9505f3901b4806839bcbc7616f.png)
(3)在(1)基础上,在直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08b9f0b9e53a83e68f5fec944f343119.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4407788e4dc88210bca71a2551d4f2f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec23c49bdf9dc11f6decfc7b35a9d01f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3fd596cec579ec99b3915ac694124597.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e0e73c9e66789010b82f863a6be057d.png)
您最近一年使用:0次
2021-12-29更新
|
870次组卷
|
3卷引用:山东省滨州市2023届高三模拟练习数学试题
名校
解题方法
7 . 将正三角形(1)的每条边三等分,并以中间的那一条线段为底边向外作正三角形,然后去掉底边,得到图(2);将图(2)的每条边三等分,并以中间的那一条线段为底边向外作正三角形,然后去掉底边,得到图(3);如此类推,将图(
)的每条边三等分,并以中间的那一条线段为底边向外作三角形,然后去掉底边,得到图
.上述作图过程不断的进行下去,得到的曲线就是美丽的雪花曲线.若图(1)中正三角形的边长为1,则图(
)的周长为__________ ,图(
)的面积为___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aceb113626093e0e431f30fa45c2c444.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/2/cc4bbbc0-a228-404d-981c-94e842b746b2.png?resizew=216)
您最近一年使用:0次
2021-08-09更新
|
1073次组卷
|
6卷引用:山东省邹平市第一中学2021-2022学年高三上学期模拟新高考一卷数学试题