05选择题5★★☆☆☆
设椭圆 C1:x2a2+y2=1C_1: \frac{x^2}{a^2} + y^2 = 1 (a>1a > 1), C2:x24+y2=1C_2: \frac{x^2}{4} + y^2 = 1 的离心率分别为 e1,e2e_1, e_2。若 e2=3e1e_2 = \sqrt{3}e_1, 则 a=a = ( )
A.
233\frac{2\sqrt{3}}{3}
B.
2\sqrt{2}
C.
3\sqrt{3}
D.
6\sqrt{6}
答案与解析

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