正数a、m、b构成公差为﹣ 12 的等差数列，a，b的等比中项是2 5 ，则双曲线 x2a2 ﹣ y2b2 =1的离心率为

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正数a、m、b构成公差为﹣

1

2

的等差数列，a，b的等比中项是2 5 ，则双曲线

x

2

a

2

﹣

y

2

b

2

=1的离心率为（）

A： $\frac{5}{3}$

B： $\frac{\sqrt{41}}{4}$

C： $\frac{5}{4}$

D： $\frac{\sqrt{41}}{5}$

上一题下一题 0.0难度选择题更新时间:2011-07-27 03:43:11

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D

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