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在平面直角坐标系xOy中,双曲线中心在原点,焦点在y轴上,一条渐近线方程为x-2...
在平面直角坐标系xOy中,双曲线中心在原点,焦点在y轴上,一条渐近线方程为x-2y=0,则它的离心率为( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101224849119850148/SYS201311012248491198501005_ST/0.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101224849119850148/SYS201311012248491198501005_ST/1.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101224849119850148/SYS201311012248491198501005_ST/2.png)
D.2
考点分析:
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