Answer:

Explanation:
The general equation of parabola :
(i)
where (h,k) = vertex of parabola
Focus = (h,k+p)
When p<0 , the parabola opens downwards.
As per given , (h,k) = (0,0)
focus = (0, –1).
i.e. h=0 , k=0 , k+p=-1 , i.e. p=-1
On substituting the value of h , k and p in (i) , we get
Equation of a parabola that opens downward, has a vertex at the origin, and a focus at (0, –1) :

