已知
是两个单位向量,且
与
的夹角为
.
(1)求
;
(2)求
与
的夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb371bd7728c6d6a16533a93924ad998.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94075193c11fe43f2396cff5a485054.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15615de1a6df206dbd081251f676578e.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26decf448101f138598842fcb5b29ae6.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8371b28073f10e07b0eb46931670d632.png)
更新时间:2023-05-02 22:42:31
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相似题推荐
解答题-问答题
|
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【推荐1】如图,在平行四边形
中,E为
的中点,
与
交于点G.
![](https://img.xkw.com/dksih/QBM/2022/5/3/2971468687147008/2971928590925824/STEM/0b9d996f-d5fe-4016-80ba-6964d11bcfb2.png?resizew=260)
(1)用
表示
.
(2)若
,四边形
的面积为
,
,求
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://img.xkw.com/dksih/QBM/2022/5/3/2971468687147008/2971928590925824/STEM/0b9d996f-d5fe-4016-80ba-6964d11bcfb2.png?resizew=260)
(1)用
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9bd19d458d51304d5b5709003af66e09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/472dfa1c1e44c00e58a4712c3dea4247.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bb8fb552b9e21dbaba74d11aa747790.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b27567d43c5b91382ee3d7ca708ee422.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad72c81de9c2b3e114bd9de26b2ebbbd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7173b357dec0dca7d6da123345089741.png)
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解题方法
【推荐2】设
,
,
都是单位向量,且
,求
的最小值.
![](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/7677fa4ecba4dd4005f5a1b52cf86b82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fa3eb5b891965ff39b3e8deaf372e3a.png)
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【推荐3】已知向量
与
的夹角为
,
,
.
(I)若
,求实数k的值;
(II)是否存在实数k,使得
?说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94075193c11fe43f2396cff5a485054.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6c0927afc571a7c966c98192040979e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3381f8f3a1a00a2311793a134d3d77a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5c030d1bb5a59602624a976a2760dfc.png)
(I)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7cb5138a03b19266f82223899a614f7.png)
(II)是否存在实数k,使得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/242b0af4f33851007b2052508dd3790e.png)
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解题方法
【推荐1】已知向量
,且
.
(1)求
的值;
(2)求
在
方向上的投影向量的坐标.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0c5e3187977619f20f40adb1361a3d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35a939b39700e2d0bc922279ea960e8b.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b195aa36a3c2753ebf08cb464c52ad1e.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b4e49d17d4ad440d37c6f4bc8daba25.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
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【推荐2】(1)已知
的三边长
,
,
,求
;
(2)在
中,已知斜边
,若长为
的线段
以点
为中点,求
的最大值?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54275b7e571660d0a9e0370fbfe5050b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dae8221601c7bd5c51fd520615581fa1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d70dc2c20619a4fc12a0cfda59af5b69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbcd299938bbce1d4d2a60dd9891ddd1.png)
(2)在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f8f88798ec42a58dccd212586382b23.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e781a2489271bfd1597cba1bb6f5887.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/878e89b6eca35e34c863e832a2c661db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed0a4b88b4458da6a0174544edfc9098.png)
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【推荐1】已知向量
,其中
,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cbd9f040a8eb2814b0ddb46259b6c94f.png)
(1)若向量
在向量
方向上的投影不小于
,求正数
的最小值;
(2)若函数
在
上有零点,求
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/779f14b1f26c9fbaea03856436ca5411.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4166972dec0aa3e8694a44eeb941a08.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cbd9f040a8eb2814b0ddb46259b6c94f.png)
(1)若向量
![](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/38387ba1cadfd3dfc4dea4ca9f613cea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
(2)若函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d8ca542fb717e4bc43aa5fb609d4738.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c8bdaef5343e279c562795290b03e39.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
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解题方法
【推荐2】在
中,角
、
、
所对的边分别为
、
、
,且
.
(1)求角
的值;
(2)已知点
为
的中点,且
,求
的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](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/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aeed8a9b09f131915df26d8109393a57.png)
(1)求角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
(2)已知点
![](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/09d27bd71d79cb19eb554175e4ef0867.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
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【推荐3】如图,设正三角形ABC的边长为1.O为
的外心,
为BC边上的
等分点,
为AC边上的
等分点,
(1)当
时,求
的值;
(2)当
时;求
的值(用
,
表示);
(参考公式:
)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1db4fe79b98486f0d4556f37d64d74f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a0876215b2fd463d151523cd3c6b447.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6faaeb653a3fc73570c131dc8a81c38d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a0876215b2fd463d151523cd3c6b447.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/30/0aa6f664-f3d9-4cba-9504-d84f8c37ee81.png?resizew=167)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6ea0392d4bd0374c8a2b12a355e4655.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18627eab55012586f5894d21a11f17f5.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294250dbd576bff3da0a1456cb9a88a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75d6fd7dea593767e588c7869c89170c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c05b9832b09731a574d4a4adf7448de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7600d2cfbdc6146db96cc545706004f6.png)
(参考公式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a35f4285af3495106d9749c741c2203a.png)
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解题方法
【推荐1】已知
,
是两个不共线的非零向量,
,
,且
与
的夹角是120º,
(1)求
的大小;
(2)记
,
,
,若向量
与
的夹角为锐角,求实数
的取值范围.
![](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/8f18996bd00253c3ad9f91780103affb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df42687a73cb92e92a3cb6e54f1edb15.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb80eb942aafb194fadc473776f35b1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/433b94c39737727e53468df419d8314a.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3eebc03129bad1dfc7d85ee62145cc7b.png)
(2)记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91a9cb32a25c2a8bb99f75633b4cd5ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ece7ff6a365f1489165649106b9a1010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cfb70dc862df380c7ed892e0e95ee492.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be64d59ac6538a0f4d79fb825e082081.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d792a2aa25763e14cc2863be3887000.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
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解题方法
【推荐2】已知两个非零向量
,
,且
,
.
(1)求
,
的夹角
;
(2)若
,求
(
)的最小值.
![](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/76f742bedabd048204f5d9e8ade68363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9adc6e5fd9b1281117e46365ebaf3a6.png)
(1)求
![](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)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d7b377eb717740840940611b75babe6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8dd1bb795c751e9b228b63734f7434f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fff6e7e2b9f2b68b1647f6350b98dc8.png)
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【推荐3】已知
,
.
(1)
,求![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a560b8ff794c12dc8d194bcd2e3f3554.png)
(2)若
与
的夹角为
,求
;
(3)若
与
垂直,求
与
的夹角.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28280aaac77be24aa72379e49b6f01e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7e7d45b34339af42c78260ca29f3af8.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1cf85ad479fb344bee99797c71e92849.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a560b8ff794c12dc8d194bcd2e3f3554.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/969604545902c9a66549a4a44ec3a3c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90ab17fd4247cdd710c363d5d3fbc5bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d5fa3de8948f50d1ce79822ff88aa91.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd4ff655de43e2bfea4ed9ae34e36de0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/969604545902c9a66549a4a44ec3a3c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/969604545902c9a66549a4a44ec3a3c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90ab17fd4247cdd710c363d5d3fbc5bd.png)
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