题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083320-66977.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083321-90366.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083321-48574.gif)
(1)若
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083321-38816.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083321-67347.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083321-11272.gif)
(2)若
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083322-79619.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083322-37115.gif)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083322-61628.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083322-93091.gif)
解析
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083322-12396.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083321-38816.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083323-97009.gif)
化简得:
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083323-86251.gif)
因为
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083321-48574.gif)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083323-56690.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083323-23462.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083324-24229.gif)
又因为
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083324-89549.gif)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083324-89030.gif)
(Ⅱ)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083324-37209.gif)
由
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083322-79619.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083324-64960.gif)
即
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083325-22090.gif)
化简得:
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083325-87012.gif)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083325-91903.gif)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083325-93169.gif)
即是
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083326-23545.gif)
解得
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083326-47270.gif)
因为
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083326-97515.gif)
且
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083321-48574.gif)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083326-57353.gif)
又
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083327-80335.gif)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083322-93091.gif)
核心考点
试题【已知点,为坐标原点,且.(1)若,求与的夹角;(2)若,求tan的值.】;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
.已知平面向量
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083311-74386.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083311-24638.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083311-72769.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083311-52753.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083311-50972.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083311-23111.gif)
(1)试求函数
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083311-48842.gif)
(2)若
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083312-26606.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083312-65650.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083311-72769.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083258-37886.gif)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083300-53709.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083253-53243.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083253-45939.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083253-16209.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083254-70995.gif)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083248-62824.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083248-62824.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083243-56467.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083243-30788.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191104/20191104083243-66497.gif)
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