Question

Equation of the parabola having focus at $(0,-3)$ and its directrix is $y=3$ is?

Answer 1

$x^2=-12y$

Given the focus of the parabola is $(0,-3)$and directrix is $y=3$

It is clear that the parabola is open downwards.

Hence its equation is of the form $x^2=-4ay$

Since $a=3$

The required equation is $x^2=-4\times 3y=-12y$