1 . 已知平面向量
,
.
(1)求
的值;
(2)若向量
与
夹角为
,求实数
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/388844fa8261916a753f1912993bd1a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/503fd5ca4c7948f7bcf158e62f667275.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3db87f99222f1705e122a6bd329c9f1.png)
(2)若向量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f0f5d6389672e98b7a226d86706c390.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c67a5673958e175b00200a75e645c73c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/290710d643ab6cd3b9edd73815b1d8ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
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解题方法
2 . 学校食堂的一个窗口共卖5种菜,甲、乙2名同学每人从中选一种或两种,且两人之间不会互相影响,则不同的选法种数为( )
A.200 | B.225 | C.250 | D.450 |
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解题方法
3 . 在
中,
为
的中点,
在边
上,
与
相交于点
,且
,
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e27e78013a8680c9211ad3af47355f35.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6910c34cfe2459d547cb455dd629e50e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5085e3cdef9ea6c564e079f745d6fdb.png)
A.![]() | B.![]() | C.2 | D.![]() |
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4 . 已知变量
之间的线性回归方程为
,且变量
之间的一组相关数据如表所示,则下列说法正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b0fffbec1fe851795dfdd448bf0d165.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/358dcb866e1ea1d3f1b9f96346bd1bab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b0fffbec1fe851795dfdd448bf0d165.png)
x | 6 | 8 | 10 | 12 |
y | 6 | m | 3 | 2 |
A.变量![]() |
B.![]() |
C.可以预测,当![]() ![]() |
D.由表格数据知,该回归直线必过点![]() |
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5 . 现要安排6名大四学生(其中4名男生、2名女生)到
,
,
三所学校实习,每所学校2人,若男生甲不安排到
学校,2名女生必须安排到不同的学校且不安排到
学校,则不同的安排方法共有______ 种.(用数字作答)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
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解题方法
6 . 若随机变量
,且
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f26c9847f64cb2eabc3169da3a9a77b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e6632e0b55dbf6d38bf9d0f6c373186.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8baff7da05b42e1b4880791f35147263.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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解题方法
7 . 在
中,
,满足此条件的
有两解,则
的取值范围为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f84bbedc96769d2c22df04745121165a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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8 . 设
为实数,若向量
.
(1)若
与
垂直,求
的值;
(2)当
为何值时,
三点共线.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0192561f4ead4f95871b50f2c2a8d5b7.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93c0f0a6242f7b1313fd149d797ef62e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef8337706c550bc095d7a2bd872221a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
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解题方法
9 . 已知
,若
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b06f37bd322af6e273ceb66bac49a716.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/969b106918cf44777d177a0538da8cb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7454629359a7e14a85da0428c1b03f36.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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解题方法
10 . 若向量
满足
,
,则
在
上的投影向量为______ (用
表示)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b172cf8d898883d82e973f28c3c3a3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7da55c225932dfff8999c7a67ef87c06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cab4a159676f892d37605751744abad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94075193c11fe43f2396cff5a485054.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
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