9514 1404 393
Answer:
y = -1/16x^2 +4
Step-by-step explanation:
The vertex is halfway between the focus and directrix, so is at (0, 4). The focus is 4 units below the vertex, so "p" = -4. For vertex (h, k) and focus-vertex distance p, the equation is ...
y = 1/(4p)(x -h)^2 +k
Using the values we determined, this is ...
y = -1/16x^2 +4
