题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083852-68002.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083852-74112.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083852-23169.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-79562.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-69162.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-61392.gif)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-17674.gif)
解析
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083854-70091.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-61392.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083854-73696.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083852-23169.gif)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083854-69774.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083854-45732.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083854-70091.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-79562.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083852-68002.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083854-70091.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-69162.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083852-74112.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083854-70091.gif)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-79562.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-69162.gif)
=5y2-20y+12=5(y-2)2-8,从而,当
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083855-76654.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-79562.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-69162.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083854-70091.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-79562.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-69162.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083855-22332.gif)
于是此时|
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-79562.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083855-49012.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-69162.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083855-98299.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-79562.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-69162.gif)
∴cosÐAPB=
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083856-93398.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083856-70269.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083853-17674.gif)
核心考点
试题【(12分)设平面内的向量=(1,7),=(5,1),=(2,1),点P是直线OM上的一个动点,求当·取最小值时,的坐标及ÐAPB的余弦值.】;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/20191104/20191104083836-23435.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083836-23513.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083837-80089.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083837-86836.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083836-23435.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083837-80089.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083837-86836.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083825-67634.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083826-25741.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083826-98204.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083826-26577.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083826-98204.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083826-16552.gif)
A.外心 | B.内心 |
C.重心 | D.垂心 |
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083821-74811.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083821-71053.png)
则实数
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083821-19574.png)
ΔABC内接于以O为圆心,1为半径的圆,且3+4+5=。①求数量积,·,·,·;②求ΔABC的面积。
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083807-95736.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083808-73785.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083808-65085.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083808-28781.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083808-23377.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083809-26487.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083809-78910.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083809-56436.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083808-65085.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083808-28781.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083809-39596.gif)
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