Let the length of the latus rectum of an ellipse with its major axis along x-axis and centre at the origin,
Question:
Let the length of the latus rectum of an ellipse with its major axis along $x$-axis and centre at the origin, be 8 . If the distance between the foci of this ellipse is equal to the length of its minor axis, then which one of the following points lies on it ?
Correct Option: , 2
Solution:
$\frac{2 b^{2}}{a}=8$ and $2 a e=2 b$
$\Rightarrow \frac{\mathrm{b}}{\mathrm{a}}=\mathrm{e}$ and $1-\mathrm{e}^{2}=\mathrm{e}^{2} \Rightarrow \mathrm{e}=\frac{1}{\sqrt{2}}$
$\Rightarrow b=4 \sqrt{2}$ and $a=8$
so equation of ellipse is $\frac{x^{2}}{64}+\frac{y^{2}}{32}=1$