Answer
$x^2=4y$
Work Step by Step
The directrix $y=-1$ is a horizontal line. So, we have a parabola with vertical axis: $(x-h)^2=4p(y-k)$, where $(h,k)$ is the vertex. Also, the focus is above the directrix. So, the parabola opens upward: $p\gt0$.
The distance between the focus and the directrix is equal to $2p$:
$2p=1-(-1)=2$
$p=1$
Given that the parabola opens upward, the vertex is $p=1$ unit below the focus:
Vertex: $(h,k)=(0,1-1)=(0,0)$
So, the vertex is the origin.
We have:
$(x-0)^2=4(y-0)$
$x^2=4y$
