What is the eccentricity of the ellipse?

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Given, Ratio of Area of rectangle formed by end points of L.R to that of ellipse is $ \frac{1}{\pi} $. Therefore,

Area of rectangle $A_1$ = Distance between focii × Length of L.R $A_1 = (2ae)(\frac{2b^2}{a}) = 4eb^2$

Area of ellipse $A_2 = \pi ab$, then:- $$ \frac{4eb^2}{\pi ab} = \frac{1}{\pi} $$

Which gives, $ \frac{b}{a} = \frac{1}{4e} $

Now for eccentricity, $$ \frac{b^2}{a^2} = 1 - e^2 $$ $$ \frac{1}{16 e^2} = 1- e^2 $$ Taking $e^2 = t $ and solving, I get,

$$ t = e^2 = \frac{2 \pm \sqrt(3)}{4} $$

I believe I should get that value for $e$ and not $e^2$. Where did I go wrong?

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You have not done anything wrong. (D) is the right answer since it squares to $\frac{2\pm\sqrt3}4$: $$\left(\frac{\sqrt3\pm1}{2\sqrt2}\right)^2=\frac{4\pm2\sqrt3}8=\frac{2\pm\sqrt3}4$$