题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044942-49291.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044942-93602.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044942-16035.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044942-19860.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044943-93507.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044943-61671.png)
(1)若
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044943-34313.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044942-49291.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044943-93507.png)
(2)当
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044944-20271.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044944-93757.png)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044944-12600.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044944-10905.png)
解析
试题分析:(1)为求向量
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044942-49291.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044943-93507.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044942-49291.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044943-93507.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044945-14844.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044945-36056.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044944-12600.png)
(2)利用向量的坐标运算,并利用三角函数的和差倍半公式,化简得到,
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044945-85071.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044945-93095.png)
试题解析:(1)∵
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044942-49291.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044942-93602.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044943-93507.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044943-61671.png)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044946-65975.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044946-95424.png)
当
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044943-34313.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044942-49291.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044946-67804.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044947-65043.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044945-14844.png)
∵
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044945-36056.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044944-12600.png)
(2)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044947-14028.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044947-85399.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044947-17762.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044945-93095.png)
∵
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044944-20271.png)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044948-20519.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044948-49850.png)
∴当
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044948-14263.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044948-95630.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044944-10905.png)
核心考点
试题【已知向量=, =, = (1)若,求向量、的夹角(2)当时,求函数的最大值】;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/20191104/20191104044938-92963.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044934-56776.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044934-44473.png)
A.![]() ![]() | B.![]() ![]() |
C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044927-48624.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044927-17626.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044927-48624.png)
A.直角三角形
B.等边三角形
C.非等边锐角三角形
D.钝角三角形
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044922-29059.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044922-74273.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044923-98196.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044923-51411.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044923-21856.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044923-66376.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044923-19386.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044924-46475.png)
A.2 | B.-2 | C.8 | D.-8 |
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044915-21856.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044915-40923.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044916-20199.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044916-95045.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044916-38824.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044915-21856.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104044915-40923.png)
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