名校
1 . 向量,且
,则
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2 . 如图,在矩形
中,已知
,且
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/435b7a3ffa8bcfcc0c02bd530c39e575.png)
__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de745f4a313e835454881b20c7fabeb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01fcaae1068e41105b6e3c3a2855318c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/435b7a3ffa8bcfcc0c02bd530c39e575.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/20/f14f4600-e9f3-4af4-911a-ea0cc0d76b35.png?resizew=149)
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2011·四川成都·一模
3 . 在
中,角A,B,C的对边分别为
,
,
,AH为BC边上的高,给出以下四个结论:
①
;
②
;
③若
,则
为锐角三角形;
④
.
其中所有正确结论的序号是____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.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)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f118d46e20e67fa5372ede6e5a396f.png)
②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14fe6084a57024d1201bef2491d7a24b.png)
③若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1c9877e9a2ec72b4dad5ad449da96be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
④
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e8a16bf5b2ab91962d0861d261e9e7f.png)
其中所有正确结论的序号是
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解题方法
4 . 四边形
中,
,
,则此四边形的面积等于__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18e7108e0dfa3582259fc181b4e8b3b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c828983e45c69501b91047b57aafea6b.png)
您最近一年使用:0次