Conic Sections Question 270

Question: The eccentricity of the ellipse $ 9x^{2}+5y^{2}-30y=0 $ , is

[MNR 1993; Pb. CET 2004]

Options:

A) 1/3

B) 2/3

C) 3/4

D) None of these

Show Answer

Answer:

Correct Answer: B

Solution:

$ 9x^{2}+{{(\sqrt{5}y-3\sqrt{5})}^{2}}=45 $ or $ \frac{x^{2}}{5}+\frac{{{(y-3)}^{2}}}{9}=0 $

therefore $ a^{2}=5, $

$ b^{2}=9 $ . Therefore $ e=\frac{2}{3} $ .