Conic Sections Question 224

Question: The latus rectum of the hyperbola $ 9x^{2}-16y^{2}-18x-32y-151=0 $ is

[MP PET 1996]

Options:

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

B) 9

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

D) $ \frac{9}{2} $

Show Answer

Answer:

Correct Answer: D

Solution:

$ 9x^{2}-18x+9-16y^{2}-32y-16=144 $

$ \Rightarrow \frac{{{(x-1)}^{2}}}{16}-\frac{{{(y+1)}^{2}}}{9}=1 $

therefore Latus rectum $ =\frac{2b^{2}}{a}=\frac{2\times 9}{4}=\frac{9}{2} $ .