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曲线的一个焦点的直线交双曲线所得的弦长为20,若这样的直线有且仅有两条,则离心率...
曲线
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101224208512270414/SYS201311012242085122704010_ST/0.png)
的一个焦点的直线交双曲线所得的弦长为20,若这样的直线有且仅有两条,则离心率为( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101224208512270414/SYS201311012242085122704010_ST/1.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101224208512270414/SYS201311012242085122704010_ST/2.png)
C.2
D.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101224208512270414/SYS201311012242085122704010_ST/3.png)
考点分析:
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A.
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