Question

Find the equation of the parabola determined by the given information. Vertex at the origin, focus at (0,-5)
1. Y^2=-20x
2. Y=-1/5x^2
3. Y^2=-5x
4. Y=-1/20x^2

Answer 1

wrong. The parabola
x^2 = 4py has vertex at (0,0) and focus at (0,p)
so we have p = -5, yielding
x^2 = -20y
or
y = -1/20 x^2

Answer 2

The correct equation of the parabola is:

1. Y^2 = -20x

Answer 3

You are correct, apologies for the error. The equation of the parabola should be:

Y = -1/20x^2