Conic Sections Question 334

Question: The eccentricity of the curve represented by the equation $ x^{2}+2y^{2}-2x+3y+2=0 $ is

[Roorkee 1998]

Options:

A) 0

B) 1/2

C) $ 1/\sqrt{2} $

D) $ \sqrt{2} $

Show Answer

Answer:

Correct Answer: C

Solution:

Equation $ x^{2}+2y^{2}-2x+3y+2=0 $ can be written as $ \frac{{{(x-1)}^{2}}}{2}+{{( y+\frac{3}{4} )}^{2}}=\frac{1}{16} $

therefore $ \frac{{{(x-1)}^{2}}}{(1/8)}+\frac{{{( y+\frac{3}{4} )}^{2}}}{(1/16)}=1 $ , which is an ellipse with $ a^{2}=\frac{1}{8} $ and $ b^{2}=\frac{1}{16} $

$ \therefore \frac{1}{16}=\frac{1}{8}(1-e^{2}) $

therefore $ e^{2}=1-\frac{1}{2} $

therefore $ e=\frac{1}{\sqrt{2}} $ .