Conic Sections Question 367

Question: The length of the latus rectum of the ellipse $ 9x^{2}+4y^{2}=1 $ , is

[MP PET 1999]

Options:

A) $ \frac{3}{2} $

B) $ \frac{8}{3} $

C) $ \frac{4}{9} $

D) $ \frac{8}{9} $

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Answer:

Correct Answer: C

Solution:

Given ellipse is $ \frac{x^{2}}{{{( \frac{1}{3} )}^{2}}}+\frac{y^{2}}{{{( \frac{1}{2} )}^{2}}}=1 $ Here $ b>a $ ;
$ \therefore $ Latus rectum $ =\frac{2a^{2}}{b}=\frac{2\times \frac{1}{9}}{\frac{1}{2}}=\frac{4}{9} $ .