题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115226-80323.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115226-30276.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115227-27860.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115227-42078.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115227-83900.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115227-14877.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115228-77950.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115228-38161.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115228-51630.png)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115228-88219.png)
解析
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115229-43547.png)
解答:解:由题意可得圆的方程一定关于y轴对称,故由-a+1=0,求得a=1
由圆的几何性质知,只有当y≤1时,才能保证此圆的方程确定的函数是一个偶函数,故0<b≤1
由此知点(a,b)的轨迹是一个线段,其横坐标是1,纵坐标属于(0,1]
又抛物线y=-
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115229-43547.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115229-43547.png)
由此可以判断出焦点F到点(a,b)的轨迹上点的距离最大距离是
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115229-16523.png)
故答案为
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115229-79339.png)
核心考点
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115211-97756.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115211-79393.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115211-27625.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115211-44626.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115211-44626.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115212-66974.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115212-26701.png)
(1)若直线
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115212-66974.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115212-25400.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115212-69701.png)
(2)设直线
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115212-90509.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115212-13177.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115213-93728.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115200-42325.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115200-46301.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115201-70687.png)
A 4 B 2 C –4 D –2
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115129-89063.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115129-66077.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115129-96730.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115129-47917.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115130-79986.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115130-30798.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115130-85084.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115130-29606.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115130-78934.png)
A.![]() | B.![]() | C.![]() | D.![]() |
(1)一条船船顶部宽4m,要使这艘船安全通过,则船在水面以上部分高不能超过多少米?
(2)近日因受台风影响水位暴涨2.7m,为此必须加重船载,降低船身,才能通过桥洞. 试问:一艘顶部宽
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115107-43331.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115108-63442.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115050-50387.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115050-13868.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115050-77693.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115050-62516.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115050-62516.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115050-62516.png)
A -4
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115050-62516.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025115050-62516.png)
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