Hello, Hockey_Guy14!
Determine an equation for the parabola with focus
and directrix
There are two types of parabola:
. .
where is the vertex
and is the distance from the vertex to the focus.
. . (It is also the distance from the vertex to the directrix.)
Graph the focus and directrix. Code:
* |
| * :
| * :
| F V :
- - + - - o - - * - - : -
| 3 5 :
| * :
| * x=7
* |
The vertex is midway between the focus and the directrix: .
. . And we see that: .
The parabola always "bends around" the focus
. . and "away from" the directrix.
This parabola opens to the left.
. Its equation is: .
Therefore, the equation is: .