过抛物线 y2=4x 的焦点作直线交抛物线于A(x1,y1)B(x2,y2)两点,如果x1+x2=6,那么|AB|= [ ]A.6 B.8 C.9
题型:安徽省期末题难度:来源:
过抛物线 y2=4x 的焦点作直线交抛物线于A(x1,y1)B(x2,y2)两点,如果x1+x2=6,那么|AB|= |
[ ] |
A.6 B.8 C.9 D.10 |
答案
B |
举一反三
试在抛物线y2=﹣4x上求一点P,使其到焦点F的距离与到A(﹣2,1)的距离之和最小,则该点坐标为 |
[ ] |
A.![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025211010-74415.png) B.![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025211010-23906.png) C.![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025211011-27502.png) D.![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025211011-84846.png) |
点P是抛物线y2=4x上一动点,则点P到点A(0,﹣1)的距离与到直线x=﹣1的距离和的最小值是 |
[ ] |
A.![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025211002-50550.png) B.![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025211003-71546.png) C.2 D.![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025211003-58798.png) |
过抛物线y2=2px(p>0)的焦点F作倾斜角为45°的直线交抛物线于A、B两点,若线段AB的长为8,则p=( )。 |
抛物线y=x2+bx+c在点(1,2)处的切线与其平行直线bx+y+c=0间的距离是 |
[ ] |
A.![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025210954-62126.png) B.![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025210955-56174.png) C.![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025210955-34214.png) D.![](http://img.shitiku.com.cn/uploads/allimg/20191025/20191025210955-61082.png) |
最新试题
热门考点