MCQ
The eccentricity of the conic ${x^2} - 4{y^2} = 1$, is
  • A
    $\frac{2}{{\sqrt 3 }}$
  • B
    $\frac{{\sqrt 3 }}{2}$
  • C
    $\frac{2}{{\sqrt 5 }}$
  • $\frac{{\sqrt 5 }}{2}$

Answer

Correct option: D.
$\frac{{\sqrt 5 }}{2}$
d
(d) Given conic is $\frac{{{x^2}}}{{{{(1)}^2}}} - \frac{{{y^2}}}{{{{\left( {\frac{1}{2}} \right)}^2}}} = 1$

$\therefore {b^2} = {a^2}({e^2} - 1)$

$⇒$ $\frac{1}{4} + 1 = {e^2}$

$⇒$  $e = \frac{{\sqrt 5 }}{2}$.

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