名校
1 . 某高校承办了奥运会的志愿者选拔面试工作,现随机抽取了100名候选者的面试成绩并分成五组:第一组
,第二组
,第三组
,第四组
,第五组
,绘制成如图所示的频率分布直方图,已知第三、四、五组的频率之和为0.7,第一组和第五组的频率相同.
、
的值;
(2)估计这100名候选者面试成绩的平均数和中位数(精确到0.1);
(3)在第四、五两组志愿者中,按比例分层抽样抽取5人,然后再从这5人中选出2人,求选出的两人来自同一组的概率.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/205eefd16b80c0b21800a3540d3e13e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13ea59cdd39c1e893fb609d05f86ded7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c56f3ccfe5a0b479ce64640a30b46520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc20387d18997336f432f9d6e81b560e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7880ec19b4c6d891686fe1774f267b7f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
(2)估计这100名候选者面试成绩的平均数和中位数(精确到0.1);
(3)在第四、五两组志愿者中,按比例分层抽样抽取5人,然后再从这5人中选出2人,求选出的两人来自同一组的概率.
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解题方法
2 . 已知等边
的边长为2,
,
,
交
于
,则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff400c098ae6bf6abd24651a5a21114e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8eeca31b6ec56f02c3ca7969e098aa6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
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解题方法
3 . 如图,已知等腰梯形ABCD中(图1),
是BC的中点,
,将
沿着AE翻折(图2),使得直线AB与CD不在同一个平面,得到四棱锥![](https://staticzujuan.xkw.com/quesimg/Upload/formula/249faccf948dabc998a1cca2f22f341e.png)
与
所成的角的大小;
(2)在线段
上是否存在点
,使得
平面
,若存在,求出
的值;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d45ba46b616686dd2ce6356687a33a6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/619e1e12cc9037b65ec7ee72160e9022.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad09a769a75b107390b9eeccc929f761.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/249faccf948dabc998a1cca2f22f341e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5e884ca9429486026caa5e2310b0e4e.png)
(2)在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f6f93171329d508d491143b9d71f7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17e5e2ba78a5b1dd0f39bb65d2a0a0f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efb87785b2842459c59b2571aac7374b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a984cf090f466bfb39d7b4dbafcf2d3d.png)
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解题方法
4 . 记
的内角A,B,C所对的边分别为a,b,c.已知向量
,
.
(1)设单位向量
,若
与
共线,且
,求A;
(2)当
且
为斜三角形时:
(i)若
,求B;
(ii)求
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f764b13bea2c7a47910f4dae02466bc0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53d8b2c3e79306d15f79decd22e1309b.png)
(1)设单位向量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e7cec07bda4ce25be78389d554134c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c778a27e4c7bbc16611c9bedec6e1f58.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1b8a88a16125366536cb4ad658e0cf1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a36ec31cfd615abfbee3ed2f4a1d8883.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7cb5138a03b19266f82223899a614f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(i)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3711c8ba16405959bcb0b70385da1d89.png)
(ii)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/413323ab92f73c1eabb235731bb5c399.png)
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解题方法
5 . 在矩形
中,E,F分别为BC,CD的中点,若
(m,
),则
的值是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1930289026d38536dbddf820e5663d46.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3276b5e12396fc4753eb3f8254f9fa68.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f32043a653eba02c79ae6395b3bcb34f.png)
A.1 | B.2 | C.![]() | D.![]() |
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解题方法
6 . 由扇形
和
组成的平面图形如图所示,已知
,
,
,
,点
在弧
(含端点)上运动.
,求
正弦值的取值范围;
(2)四边形
面积为
,求
的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa16146cb21f11693feffb0876c0795b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ebcc52a06d806fde891e09a0a389fcd4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ba1df94176a1f769c7a0a12bf357fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8dcca60ba6144abbf47abd51d1f63f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5d8b7bfeb5a4829b4db31e1d74a8c1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef0402dd5ae3db10281f9f1e11738bcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f90c780dac29ff8b7df5881d3b33abab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2460507a462453e084eaf70a7d867e9.png)
(2)四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3740e101f0d49f386901c49f55efbc0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
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解题方法
7 . 如图,已知正方体
的棱长为
.
平面
;
(2)求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4645450a006f2c20087486d0833afbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/239198e40085b7dcffbe747c9c265a05.png)
(2)求点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/239198e40085b7dcffbe747c9c265a05.png)
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8 . 设
,
,
为复数,下列命题中正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af68f652b4c13657ffddf3c9e7eb262b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa224ed9be8766a4d0b5138bd57de0f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a67a742d2a43e907fb1c3a1bdf1d6a9.png)
A.若![]() ![]() ![]() |
B.若![]() ![]() ![]() |
C.若![]() ![]() |
D.若![]() ![]() |
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9 . 在棱长为2的正方体
中,若在线段
和线段
上分别取点E,F,使得直线
平面
,则EF的长的最小值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8772aa893a9c1d40f714cb25701701.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e539f26ed5e0b20ff7220559324869a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06222ee533c2484ab25321a6abbf98cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b4cd2b33bd983a9ed6575b9de04a46a.png)
A.![]() | B.1 | C.![]() | D.![]() |
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解题方法
10 . 如图,在正方形
中,E,F分别是BC,CD的中点,现在沿AE,AF及EF把这个正方形折成一个空间图形,使B,C,D三点重合,重合后的点记为G,且取EF中点为O,则在这个空间图形中必有( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次