Question 443965: Hey, I have question about finding a equation for a parabola with a focus of (3,4) and a directrix of Y=2. After finding the equation, I have to graph it, but my math book is not very helpful on this matter, I had to miss class the day before when we went over them and I have a hard time learning out of a book rather than interacting with someone else.
Anyways, thanks for any help that you might be able to offer, and my name is Wayne. Thanks again.
Answer by scott8148(6628)   (Show Source):
You can put this solution on YOUR website! the vertex is midway between the focus and the directrix ___ in this case, (3,3)
the general vertex form is ___ y = a(x - h)^2 + k ___ where (h,k) is the vertex
a is equal to ___ 1 / (4p) ___ where p is half the distance from the directrix to the focus
___ the sign of a is determined by the direction FROM the directrix TO the focus
your equation is ___ y = (1/4)(x - 3)^2 + 3
starting with the vertex, and working in both directions
___ plug in values for x
___ calculate the corresponding y values
___ plot the points
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