Ellipse Question 3

Question 3 - 2024 (29 Jan Shift 1)

If the points of intersection of two distinct conics $x^{2}+y^{2}=4 b$ and $\frac{x^{2}}{16}+\frac{y^{2}}{b^{2}}=1$ lie on the curve $y^{2}=3 x^{2}$, then $3 \sqrt{3}$ times the area of the rectangle formed by the intersection points is

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Answer (432)

Solution

Putting $y^{2}=3 x^{2}$ in both the conics

We get $x^{2}=b$ and $\frac{b}{16}+\frac{3}{b}=1$

$\Rightarrow b=4,12 \quad(b=4$ is rejected because curves coincide $)$

$\therefore b=12$

Hence points of intersection are

$( \pm \sqrt{12}, \pm 6) \Rightarrow$ area of rectangle $=432$