Conic Sections Question 341
Question: If the centre, one of the foci and semi-major axis of an ellipse be (0, 0), (0, 3) and 5 then its equation is
[AMU 1981]
Options:
A) $ \frac{x^{2}}{16}+\frac{y^{2}}{25}=1 $
B) $ \frac{x^{2}}{25}+\frac{y^{2}}{16}=1 $
C) $ \frac{x^{2}}{9}+\frac{y^{2}}{25}=1 $
D) None of these
Show Answer
Answer:
Correct Answer: A
Solution:
Centre (0, 0), focus (0, 3), $ b=5 $ Focus (0, 3)
therefore $ be=3 $
therefore $ e=3/5 $
therefore $ a=b\sqrt{1-e^{2}}=4 $
Hence the required equation is $ \frac{x^{2}}{16}+\frac{y^{2}}{25}=1 $ .
BETA
