解题方法
1 . 已知平面向量
,
,
,其中
,
(1)若
为单位向量,且
,求
的坐标;
(2)若
且
与
垂直,求向量
,
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb80eb942aafb194fadc473776f35b1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/433b94c39737727e53468df419d8314a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb573cc0f30d5c32cdad1510793f0e7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aedaec4e632c9981ce15f49b3f736706.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb573cc0f30d5c32cdad1510793f0e7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9c13327875f7ecbfe021841d6f681a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb573cc0f30d5c32cdad1510793f0e7b.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31ed729f3b3877d0217653620bb867e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e03adf3fa0262d9bd46a2c794eb15746.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7e07c25df57a36d4f1b11d7d9fe16b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb80eb942aafb194fadc473776f35b1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/433b94c39737727e53468df419d8314a.png)
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解题方法
2 . 已知
是
的重心,角
所对的边
满足
,且
,若
为平面
内一点,则
的最小值是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daf23724646026bc00ba6cdf5d52a303.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e258ab9e600435b37465092243d99f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4375c2e6043d6b700c7f1ca0609d6109.png)
A.-2 | B.![]() | C.![]() | D.-1 |
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3 . 已知
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6c57bbef89a37f1a3808c0ceeac0c22.png)
_________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d853fa400b5ca554acff9e008fe3bb6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6c57bbef89a37f1a3808c0ceeac0c22.png)
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解题方法
4 . 已知
,
,若
与
的夹角为锐角,则
的取值范围为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddac50ca9d89729c6ac4a5d687bd3b0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dee7fd9bb7fff238f4fd52262196921.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb80eb942aafb194fadc473776f35b1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/433b94c39737727e53468df419d8314a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
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5 . 在△ABC中,CA=2CB=2,·
=-1,O是△ABC的外心,若
=x
+y
,则x+y=
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名校
6 . 如果向量
与
的夹角为
,那么我们称
为向量
与
的“向量积”,
是一个向量,它的长度
,如果
,
,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65b0cb9f6ed923e6c58e8312c96c769e.png)
__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a92e6eba8dab638fd66831cd3a0b6d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/427fa45527d0ce469bfd060bf6f991f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1674d14213c4d560adf90778bba1825.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a92e6eba8dab638fd66831cd3a0b6d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/427fa45527d0ce469bfd060bf6f991f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1674d14213c4d560adf90778bba1825.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66558cfadb748daba7767919d335ce87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd88b628fffac73eb6963e0d8e225e72.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4414868cf52b40a6ce7715727f28b0d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bad371753f8949c39c318f987d1f7c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65b0cb9f6ed923e6c58e8312c96c769e.png)
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