Posted by Jon on .
Identify the equation of a parabola whose focus is at (5,1) and whose directrix is x=3.
vertex=(5,1)
p=6
4p=24
(x5)=(24)(y+1)^2
I got it wrong

Math 
MathMate,
Hint:
The focus is at (5,1), and the directrix is at x=3, so the vertex lies halfway between the two.
The value of p is the distance between the vertex and the focus.
Wiki has an excellent article on the subject.
http://en.wikipedia.org/wiki/Parabola