Ok, I've been given this:
and I have to find the vertex, focus, and directrix of this graph.
I know how to find the vertex. In this case, it is at the origin. However, I don't have the slightest idea how to find the focus or the directrix.
Help would be appreciated here
The directrix should never touch the parabola and a perpendicular drawn to the directrix from the vertex will have length , which is why we must have the line .
Edit: Your book has the wrong focus.