名校
解题方法
1 . 在
中,角A,B,C的对边分别是a,b,c,已知
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72511f149a1b13af02d0e1421d3a63a5.png)
____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2fa98bee3bda8f0b5d89d60ff02576c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72511f149a1b13af02d0e1421d3a63a5.png)
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名校
解题方法
2 . 如图,在同一个平面内,三个单位向量
,
,
满足条件:
与
夹角为α,且
,
与
的夹角为45°.若
,求
的值______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4f605ec0729ce6d72237ad662a06862.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fc9656d8286c4d6fa309d6ae347c89e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef8337706c550bc095d7a2bd872221a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4f605ec0729ce6d72237ad662a06862.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef8337706c550bc095d7a2bd872221a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbc1d1b8795e1ce1fa500896959e0271.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fc9656d8286c4d6fa309d6ae347c89e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef8337706c550bc095d7a2bd872221a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42265933dae87584f29c6c9f294eba1e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1019d4ad2e3fb4a7abb66e0e9e55b556.png)
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