150k views
3 votes
Find the focus and directrix of the parabola with the equation x² = -22y.

User OrPo
by
5.0k points

1 Answer

4 votes

9514 1404 393

Answer:

focus: (0, -5.5)

directrix: y = 5.5

Explanation:

The equation compares to the form ...

x² = 4py

where 4p = -22 ⇒ p = -22/4 = -5.5.

The value of p is the distance from the vertex to the focus. The negative value means the focus is below the vertex at (0, -5.5).

The directrix is above the vertex by the same amount, so is y = 5.5.

Find the focus and directrix of the parabola with the equation x² = -22y.-example-1
User Cercxtrova
by
4.5k points