题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104042135-39824.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104042135-79930.png)
答案
解析
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104042136-84090.jpg)
以A为坐标原点,AB所在的直线为x轴,AD所在的直线为y轴,建立平面直角坐标系,则A(0,0),B(2,0),D(0,2),E(1,2),
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104042135-39824.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104042135-79930.png)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104042135-39824.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104042135-79930.png)
核心考点
试题【已知正方形ABCD的边长为2,E为CD的中点,则·=________.】;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
A.1 | B.-1 | C.2 | D.0 |
题型:b|sin θ(其中θ为向量a与b的夹角),a×b的方向与向量a,b的方向都垂直,且使得a,b,a×b依次构成右手系.如图所示,在平行六面体ABCD-EFGH中,∠EAB=∠EAD=∠BAD=60°,AB=AD=AE=2,则(
×
)·
=( )
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104042126-22030.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104042126-38949.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104042126-74677.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104042126-57190.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104042126-22030.jpg)
A.4 | B.8 | C.2![]() | D.4![]() |
A.-![]() | B.![]() | C.-1 | D.1 |
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104042114-39040.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104042114-18661.png)