【题文】如图所示,已知函数图像上的两点A、B和函数上的点C,线段AC平行于y轴,三角形ABC为正三角形时,点B的坐标为,则的值为________.
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【题文】如图所示,已知函数
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092619-31043.png)
图像上的两点A、B和函数
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092620-80140.png)
上的点C,线段AC平行于y轴,三角形ABC为正三角形时,点B的坐标为
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092620-86410.png)
,则
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092621-45952.png)
的值为________.
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092621-90098.jpg)
答案
【答案】
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092621-41869.png)
解析
【解析】由题意,设
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092621-12052.png)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092622-57500.png)
,即
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092622-38475.png)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092622-30071.png)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092623-32129.png)
,且
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092623-39384.png)
;因为三角形为正三角形,所以
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092623-88115.png)
;所以
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092624-13486.png)
,解得
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092624-27167.png)
;则
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092624-60955.png)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092625-48874.png)
.
考点:对数的运算、对数恒等式.
举一反三
【题文】不等式
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092613-12608.png)
的解是____________________.
【题文】设
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092558-10644.png)
,则( )
【题文】不等式
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092533-42763.png)
的解是____________________.
【题文】
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092455-44544.png)
是
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092455-33229.png)
上的偶函数,当
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092455-68527.png)
时,有
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092455-82350.png)
,且当
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092455-64017.png)
时,
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092456-50644.png)
,则
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092456-90310.png)
A.![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092456-88150.png) | B.![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092456-58899.png) | C.-1 | D.1 |
【题文】设
![](http://img.shitiku.com.cn/uploads/allimg/20200330/20200330092447-67127.png)
,则( )
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