已知单位向量
与
的夹角为α,且cos α=
,向量
与
的夹角为β,求β的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05b28baf17059c56ee9ad1ae4814acd8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b04618e5b2db68f2de6ba68972c505c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dac452fbb5ef6dd653e7fbbef639484.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6501336daf325c2f918ef54f84e45307.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3668a3c45a9d4fbd043fd848f635406b.png)
21-22高一下·全国·课前预习 查看更多[1]
(已下线)6.2.4向量的数量积(第二课时)-【高效导学】2021-2022学年高一数学下学期同步精品导学案(人教A版2019必修第二册)
更新时间:2022-03-22 09:04:30
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解答题-问答题
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适中
(0.65)
名校
解题方法
【推荐1】已知向量
,
.
(1)若
,求实数
的值;
(2)已知向量
与
的夹角为钝角,求实数
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/108bba6658ac059e649b212650061240.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c0f5cb03f5d636e127afa281ff5db34.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b19e9066e6ebe86de2108970c51a8b88.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
(2)已知向量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b45ba716f03748c19b7ce2f99af536ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
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解答题-问答题
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适中
(0.65)
【推荐2】已知向量
的夹角为
,且
,
,设
,
.
(1)试用t来表示
的值;
(2)若
与
的夹角为钝角,试求实数t的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8ccba3b87a8a48ac3dd5f72d00bdb1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd18461fd9d77e6fa46a654f0ab540f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/082c6926889f84f438ea35f70bf05f02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e823fa8d47666d2a61f3eaf7587131e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66b3b75ddeff746c22973e8b84fb6ff2.png)
(1)试用t来表示
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/741574f71252839af5c088cf224bf159.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/560ee2894ba8c5cee6633430cc8b3b41.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36f1a8e551cba7ec9f451749f60e628d.png)
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解答题-问答题
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适中
(0.65)
名校
【推荐1】已知向量![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ddf124cc4d1524fd2303d65b774038c.png)
(1)当
时,求
的值;(2)若
为锐角,求
的范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ddf124cc4d1524fd2303d65b774038c.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c125f47616ce39e4616309905d0899e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/897de0df886562999d8d132705d49ba4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
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解答题-证明题
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适中
(0.65)
【推荐2】已知
是两个单位向量,
,且
.
(1)求
的夹角;
(2)若D为线段BC上一点,DC =2BD,求证:AD⊥AB.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1238a7a8ce9db1a47ae0ac80d5ed70cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611ab4e3ede21cd03d0cf99675d9ed22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce69b7bf1677649ee5121f8a884f6f44.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1238a7a8ce9db1a47ae0ac80d5ed70cf.png)
(2)若D为线段BC上一点,DC =2BD,求证:AD⊥AB.
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