解题方法
1 . 已知向量
,若
三点共线.
(1)求实数
的值;
(2)若
,求
的坐标;
(3)求
在
方向上的投影.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56900282673cd47dc14b0e0a5413c8bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7915e42fb51e0e5d082d01768618e3e6.png)
(1)求实数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/524156ae1ea772e32a0d894b8c905072.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/433b94c39737727e53468df419d8314a.png)
(3)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9795e7f5cb9b366776c41d8f3f43942.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f75fc81977aee721525b4c5625f5a097.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 .
所在平面内一点
满足
,若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a18798408a1b91fdb12deb79f0b562a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcf25c248a27651e84dc9e270a6b2802.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e2d7ec3ab513b8ce3ca2d7bf7b3ad95.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a18798408a1b91fdb12deb79f0b562a.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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名校
4 . 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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