Question

How do you find the standard form of the equation of the parabola with Vertex at the origin, focus at (0, -4)?

Answer 1

`x^2=-16y`

Explanation:

graph{x^2=-16y [-10, 10, -5, 5]} The vector `VS` joining the vertex

V(0, 0) and the focus, down at S(0, -4), designates the axis of the

parabola.

So, the axis is y-axis, in the negative direction...

The size of the parabola is VS = a = 4.

Easily, the equation is `x^2=-4ay=-16y`. See the graph.