题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185347-79907.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185347-77522.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185348-32787.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185348-28997.jpg)
(1)求椭圆的方程.
(2)已知定点E(-1,0),若直线y=kx+2(k≠0)与椭圆交于C、D两点.问:是否存在k的值,使以CD为直径的圆过E点?请说明理由.
答案
(1)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185348-10571.gif)
(2)存在
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185348-67864.gif)
解析
依题意
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185349-79036.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185349-46900.gif)
∴ 椭圆方程为
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185348-10571.gif)
(2)假若存在这样的k值,由
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185349-91110.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185349-48269.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185350-58728.gif)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185350-61654.gif)
设
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185350-24487.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185350-11175.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185350-40298.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185351-20108.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185351-89318.gif)
而
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185351-58831.gif)
要使以CD为直径的圆过点E(-1,0),当且仅当CE⊥DE时,
则
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185351-53353.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185352-86329.gif)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185352-14626.gif)
将②式代入③整理解得
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185348-67864.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185348-67864.gif)
综上可知,存在
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185348-67864.gif)
核心考点
试题【已知椭圆(a>b>0)的离心率,过点A(0,-b)和B(a,0)的直线与原点的距离为.(1)求椭圆的方程.(2)已知定点E(-1,0),若直线y=kx+2(k≠】;主要考察你对椭圆的定义与方程等知识点的理解。[详细]
举一反三
已知椭圆的两
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185334-87440.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185335-30422.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185335-13686.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185335-73157.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185335-61383.gif)
(I)求椭圆的方程;
(Ⅱ)若过点(1,0)的直线
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185336-24279.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185336-17624.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185336-37668.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185336-28356.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185318-77063.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185318-21885.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185319-90655.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185319-79994.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185319-59844.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185319-81930.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185319-28189.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185320-95266.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185318-21885.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185320-90600.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185320-23843.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185320-10979.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185320-23071.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185320-95266.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185320-90600.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185320-10979.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185320-70469.gif)
(1)当
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185321-82269.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185319-28189.gif)
(2)当
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185321-89387.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185321-87433.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185308-19450.gif)
已知椭圆C上的点
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185308-94133.gif)
(Ⅰ)求椭圆C的方程和焦点坐标;
(Ⅱ)过椭圆C的焦点F2作AB的平行线交椭圆于P、Q两点,求△F1PQ的面积.
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185309-33930.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185254-88826.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185254-56143.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185254-71318.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185254-25609.gif)
(1)当直线
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185254-56143.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185254-85574.gif)
(2)当三角形OAB的面积取得最大值时,求椭圆E的方程.
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185244-22543.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185245-89327.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185245-76222.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185245-76864.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023185245-54375.png)
A.![]() | B.![]() | C.![]() | D.![]() |
最新试题
- 1— What is the____of the 2010 World Expo(世博会)? — It is “Bette
- 2设函数的定义域为,值域为,若的最小值为,则实数的值为( )A.B.或C.D.或
- 3对于做平抛运动的物体,以下说法正确的是( )A.若只将其抛出点的高度增加一倍,则它在空中运动的时间也增加一倍B.若只将
- 4西亚一些石油输出国里外来人口超过本地人口,其主要原因是[ ]A.本国人口稀少,人口老化B.经济发展水平高,能提供
- 5—What do you think of the meal we have just had?—It is well
- 6【题文】的定义域为( )A.B.C.D.
- 7There was no food in the house, _____ we rang out for a pizz
- 8如图,在平面直角坐标系中,A(-3,0),点C在y轴的正半轴上,BC∥x轴,且BC=5,AB交y轴于点D,OD=.(1)
- 9专家预测,未来十年内,我国石油生产的“龙”将是[ ]A.黑龙江 B.辽宁 C.山东 D.新疆
- 10【题文】依次填入下面横线处的句子,语意连贯、音节和谐的一组是
热门考点
- 1在某无色透明的酸性溶液中,能共存的离子组是 ( )A.Na+、K+、SO、HCOB.Cu2+、K+、SO、NOC
- 2将鲤鱼细胞中的某种物质注入鲫鱼的受精卵中,结果由该受精卵发育成的鲫鱼具有鲤鱼触须,这种生物技术和注射的物质分别是[
- 32013年3月17日上午,十二届全国人大一次会议圆满完成各项议程胜利闭幕。***主席阐述中国梦、李***总理答记者问并约法
- 4下面的折线图描述了某地某日的气温变化情况,根据图形情况,根据图形提供的信息,下列结论错误的的是[ ]A.这一天的
- 5下列反应过程符合如图所示关系的是A.向Ba(NO3)2溶液中通入SO2气体至过量B.向Na2SiO3溶液中通入HCl气体
- 6He has got _______ uncles. [ ]A. a B. one C. an D. t
- 7填补下列名句的空缺处或按要求填空。小题1:春蚕到死丝方尽, 。小题
- 8x、y满足约束条件x+y≥1x-y≥-12x-y≤2,若目标函数z=ax+by(a>0,b>0)的最大值为7,则3a+4
- 9面对高企的房价,各地纷纷出台调控举措,很多地方开始实施限购令。“限购令”就是对房价过高、上涨过快的城市在一定时间内限定居
- 10下列有关水的说法错误的是( )A.自来水是混合物B.水蒸发时水分子的体积会变大C.降低水的硬度可用煮沸的方法D.软水和