题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230117-80856.png)
A.随着![]() | B.随着![]() |
C.随着![]() | D.随着![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230117-35103.jpg)
答案
解析
以A,B为焦点且过点D的双曲线 2c=AB=4 c=2
AD=
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230117-92434.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230118-85077.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230118-46155.png)
e1=
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230118-17798.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230117-34737.png)
以C,,D为焦点且过点A的椭圆
2c=2 c=1
2a=AD+AC AC=BD
2a=
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230119-40880.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230119-64917.png)
e1 e2=
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230119-14087.png)
随着θ角增大 e1减小,e1 e2不变
核心考点
试题【如图,在等腰梯形ABCD中,AB∥CD,且AB=2CD,设 ,以A,B为焦点且过点D的双曲线离心率为e1,以C,D为焦点且过点A的椭圆的离心率为e2,则( 】;主要考察你对相似三角形的判定及有关性质等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230107-60977.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230108-12122.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230108-98032.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230108-88246.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230108-55963.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230108-88246.png)
(Ⅰ) 若
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230109-29249.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230109-37256.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230109-63386.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230109-23877.png)
(Ⅱ) 求四边形
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230109-37256.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230110-53090.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230100-81855.png)
(1)D、N、M三点共线;(2)若四边形ABCD为正方形,则DN=BN.
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230101-47526.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230101-83567.png)
A.60° | B.80° | C.120° | D.100° |
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191107/20191107230050-56758.png)