1 . A、B相互独立,
,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2731eecd8ff3e2264eebfd7cbbaaea1b.png)
_________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8d493dbdf4efe16ac774db2a02cf3af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd061e199e9d763a2b5857e6f8ada09c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2731eecd8ff3e2264eebfd7cbbaaea1b.png)
您最近一年使用:0次
名校
2 . 已知甲组数据
,
,…,
的茎叶图如图所示,其中数据的整数部分为茎,数据的小数部分(仅一位小数)为叶,例如第一数据为5.3.
、方差
、中位数M;
(2)乙组数据为
,
,…,
,且甲、乙两组数据合并后的30个数据的平均值
,方差
,求乙组数据的平均值
和方差
,写出必要的计算过程和步骤.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5bbae9353140c2235610852d04a9a3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/848dac3d6db7c23c58f399970b3f9b18.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dfbc29b47b83fdc5368770b7b1acb439.png)
(2)乙组数据为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b715e7842b95f654f16056a7c7f2abe9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13423c094861baf4b759b7f3d8c3c226.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12a9f28d2342d61e9fae0744b0a8a1cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b382035a4e07f9a8679d024bf1f7b7fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5cf8479865093acc003149c1f00fd73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c0da8a9d862e0005c44a8cb8fd262bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab1295cbd36fdc55a55b549aa2dd5887.png)
您最近一年使用:0次
3 . 已知
,椭圆
,点
是该椭圆的右焦点,过点
的直线
与椭圆
交于不同的
两点.
(1)当
且
的斜率为1时,求
;
(2)当
时,求
的取值范围;
(3)是否存在实数
,使得对于任意的直线
、
都不是直角三角形.若存在,求出所有满足条件的
;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40e72f6b2ef3329828cb8fc873eeba7c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4203a35ca9d3174d600fffc3dae1ea63.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b62769b7177ef4bc952dc1dd51d6b510.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b94469fd19f40116e2dec334919d6586.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01c74a907dda6bb7d9d56d009d9df253.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd876a2ed79c64bacc3e64b8ee92735e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f4dfec890cdfdda355e19463f3be813.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7aed39f5aca78934fb383402433fe549.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd82dde0343bdcd7822f076bf5859e39.png)
(3)是否存在实数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad4dd3be7b5428975bc9100f2d33732.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/004104bafb5f30338123d4ea2b7fedde.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
您最近一年使用:0次
名校
解题方法
4 . 冬奥组委会启动志愿者全球招募,仅一个月内报名人数便突破60万,其中青年学生约有50万人.现从过50万青年学生志愿者中,按男女分层抽样随机选取20人进行英语水平测试(满分100分),所得成绩(单位:分)统计结果用茎叶图记录如图:
(2)分别求出样本数据中男生成绩的平均数
和方差
,女生成绩的平均数
和方差
,并根据所得数据对比男生与女生在这次测验中的表现.(结果精确到0.1)
(2)分别求出样本数据中男生成绩的平均数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfbe7f95b5d89f9409ec24536da9e826.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b961e92a998a0c9d600e6b3d503adf53.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb525270c748eddaaecc4a549cca250e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2742776ecea3fdd7ef4b8a0e4a9db46.png)
您最近一年使用:0次
名校
解题方法
5 . 已知正四面体
的棱长为3,点
在棱
上,点
在线段
上,且
.
在棱
的中点处,求证:
平面
;
(2)如图2,若
,求三棱锥
的体积;
(3)如图3,当点
在棱
上移动时,求线段
长度的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb91cb9a5a14169845d700fbd95890ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97f30533da2e1d2a958dc906c37eba9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
(2)如图2,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71fa9bb19d1d32270248f377363cd96a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/209e3b87346e057276f0692a7361e446.png)
(3)如图3,当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
您最近一年使用:0次
名校
解题方法
6 . 如图,在棱长均为1的正三棱柱
中,点
在棱
上,且
.记
,
,
.
表示
、
;
(2)求直线
与直线
所成角的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d47ed867750dba3df7a4834827f272c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ef36fa79d02dd76e9ac5fda1689268f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4f8173bb7787b6b107acfe767dd1d91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df107a0db8e7084e46cbf0edc9dd4878.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e12e95f703ad30ab9a3d38376830989.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89265cbe3abc6b966ce8967fead448b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d021a5c98388463d577675e58068aa7.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
您最近一年使用:0次
名校
解题方法
7 . 已知双曲线
和直线
,
是双曲线
的左,右顶点,
是双曲线
上异于
两点的任意一点,直线
分别交直线
于
两点,设
的外接圆面积分别为
,则
的最小值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c811383baffa76f1613690882107088.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b11449658adfc07dcf4fc0b25e7ed7c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01c74a907dda6bb7d9d56d009d9df253.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b94469fd19f40116e2dec334919d6586.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b94469fd19f40116e2dec334919d6586.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01c74a907dda6bb7d9d56d009d9df253.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcaebaf8ceed245eba896f36d8ff14b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3219d10bd16516a355e800e05426c1f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3637753af5ce86be9c23a9beb6b5067.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/235f0a6fb218d28383e6f27f2df1f50f.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次
名校
解题方法
8 . 已知
,直线
与双曲线
相交于不同的点
.
(1)若点
分别在双曲线的左、右两支上,求
的取值范围;
(2)若以线段
为直径的圆,经过坐标原点,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5aff8d9b6533ff319420cdc5e8740b04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6767830cc1811f0f4ea5a008fdc7e723.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f11a4314f30e0a5a7cfb2e290751fec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01c74a907dda6bb7d9d56d009d9df253.png)
(1)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01c74a907dda6bb7d9d56d009d9df253.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
(2)若以线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
您最近一年使用:0次
名校
解题方法
9 . 在一个阳光明媚的周末,市射击俱乐部举办了一场盛大的射击比赛,来自各地的射击爱好者纷纷报名参加,甲乙作为一个组合报名参加了射击小组赛.该项比赛规则为:每个小组2人,每人每轮依次射击一次,共有2轮.若两人合计射中靶心次数不少于3次,则称这组为“神枪手组合”.已知甲、乙射中靶心的概率分别为
和
,若
,那么甲乙小组最后获得“神枪手组合”称号的最大可能性为________ (假设所有选手每次射击都互相独立).
![](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/69591a18bca3d2941ea1acb244ff7971.png)
您最近一年使用:0次
名校
10 . 双曲线
的渐近线斜率的绝对值是________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1892b7c3cd7bea116f532f66fba44662.png)
您最近一年使用:0次