Focus: ( 4, 1 )
Directrix: y = 5
The vertex is always half of a distance between the focus and the directrix.
The vertex must be at: ( 4, 3 ), h = 4, k = 3
|p| is the distance between the vertex and the directrix ( which is over the vertex and p is negative ). p = - 2
The equation:
( x - h )² = 4 p ( y - k )
( x - 4 )² = -8 ( y - 3 )
