Conic Sections Question 357

Question: $ x^{2}-4y^{2}-2x+16y-40=0 $ represents

[DCE 1999]

Options:

A) A pair of straight lines

B) An ellipse

C) A hyperbola

D) A parabola

Show Answer

Answer:

Correct Answer: C

Solution:

$ x^{2}-2x-4y^{2}+16y-40=0 $

therefore $ (x^{2}-2x)-4(y^{2}-4y)-40=0 $

therefore $ {{(x-1)}^{2}}-1-4[{{(y-2)}^{2}}-4]-40=0 $

therefore $ {{(x-1)}^{2}}-4{{(y-2)}^{2}}=25 $

therefore $ \frac{{{(x-1)}^{2}}}{25}-\frac{{{(y-2)}^{2}}}{25/4}=1 $ , which is a hyperbola.