MCQ
An equilateral triangle whose two vertices are $(-2,0)$ and $(2,0)$ and which lies in the first  and second quadrants only is circumscribed by a circle whose equation :-
  • A
    $ \sqrt 3 x^2 + \sqrt 3y^2 - 4x - 4 \sqrt 3 = 0$
  • B
    $\sqrt 3 x^2 + \sqrt 3 y^2 - 4x + 4 \sqrt 3 y = 0$
  • C
    $\sqrt 3 x^2 + \sqrt 3 y^2 - 4y + 4 \sqrt 3 = 0$
  • $\sqrt 3 x^2 + \sqrt 3 y^2 - 4y - 4 \sqrt 3 = 0$

Answer

Correct option: D.
$\sqrt 3 x^2 + \sqrt 3 y^2 - 4y - 4 \sqrt 3 = 0$
d
Let $A \equiv(-2,0)$ and $B \equiv(2,0) .$ The centre of the circle is the centroid of the equilateral trinagle.

$\therefore $ $0 \equiv\left(0, \frac{2}{\sqrt{3}}\right)$ and $\mathrm{OA}=\frac{4}{\sqrt{3}}$

$\therefore $ Required circle is

$(x-0)^{2}+\left(y-\frac{2}{\sqrt{3}}\right)^{2}=\frac{16}{3}$

i.e. $\sqrt{3} x^{2}+\sqrt{3} y^{2}-4 y-4 \sqrt{3}=0$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free