题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072523-30633.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072524-35669.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072524-74884.png)
A.-![]() | B.![]() | C.-![]() | D.![]() |
答案
解析
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072524-85999.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-18977.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-20623.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-10889.png)
解答:解:由
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072524-85999.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-73513.png)
D为BC边的中点,
由向量加法的平行四边形法则可得:
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072524-85999.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072526-52763.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072526-52109.png)
=
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072526-52763.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-10889.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-20623.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-18977.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072526-52763.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-10889.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-20623.png)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-18977.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072524-85999.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072526-52763.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-10889.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-20623.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072526-52763.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-10889.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-20623.png)
=
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072526-11285.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-10889.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-20623.png)
又∵AB=2,AC=1
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072525-18977.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072524-85999.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072526-17183.png)
故选:C
核心考点
试题【在△ABC中,AB=2,AC=1,=,则的值为A.-B.C.-D.】;主要考察你对平面向量数量积的意义等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072519-96191.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072520-79949.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072520-70692.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072520-88692.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072512-85050.png)
A.![]() | B.![]() | C.![]() | D.1 |
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072507-78702.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072507-53176.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072507-16637.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072508-20871.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072507-16637.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072508-74853.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072502-98853.png)
A.内心 | B.垂心 | C.重心 | D.外心 |
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072456-32937.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072456-74168.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072457-78665.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072457-79109.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104072457-72777.gif)
A.![]() ![]() | B.![]() | C.![]() | D.![]() |
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