1. **State the problem:**
We need to find the equation of a parabola given its focus at $(0, -5)$ and its directrix $y = 11$.
2. **Recall the definition of a parabola:**
A parabola is the set of all points equidistant from the focus and the directrix.
3. **Formula for a parabola with vertical axis:**
If the focus is at $(h, k)$ and the directrix is $y = d$, the parabola's equation is given by:
$$ (x - h)^2 = 4p(y - m) $$
where $p$ is the distance from the vertex to the focus (or directrix), and the vertex $(h, m)$ lies midway between the focus and directrix.
4. **Find the vertex:**
The vertex's $y$-coordinate is the midpoint between the focus $y$-coordinate $-5$ and directrix $y$-coordinate $11$:
$$ m = \frac{-5 + 11}{2} = \frac{6}{2} = 3 $$
The vertex is at $(0, 3)$ since the focus $x$-coordinate is $0$.
5. **Calculate $p$:**
$p$ is the distance from the vertex to the focus:
$$ p = k - m = -5 - 3 = -8 $$
The negative sign indicates the parabola opens downward.
6. **Write the equation:**
Using the formula:
$$ (x - 0)^2 = 4 \times (-8) (y - 3) $$
which simplifies to:
$$ x^2 = -32(y - 3) $$
7. **Final answer:**
The equation of the parabola is:
$$ \boxed{x^2 = -32(y - 3)} $$
Parabola Equation C8Dcb3
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