SOLUTION: Find the equation for the parabola that has its vertex at the origin and the focal point is 296 units above the directrix.

Algebra ->  Equations -> SOLUTION: Find the equation for the parabola that has its vertex at the origin and the focal point is 296 units above the directrix.      Log On


   



Question 970223: Find the equation for the parabola that has its vertex at the origin and the focal point is 296 units above the directrix.
Answer by AnlytcPhil(1806) About Me  (Show Source):
You can put this solution on YOUR website!
Find the equation for the parabola...
Its equation is  

%28y-k%29%5E2%22%22=%22%224p%28x-h%29 if it opens up or down, 
with directrix y=k-p and focus (0,k+p) 
if p is positive it opens up, if p is negative it opens down.

or

{{(x-h)^2}}}%22%22=%22%224p%28y-x%29 if it opens right or left.
with directrix x=h-p and focal point (h+p,0)
if p is positive it opens right, if negative it opens left.

...that has its vertex at the origin
So h=0 and k=0

Its equation is  

y%5E2%22%22=%22%224px if it opens up or down, 
with directrix y=-p and focus (0,p) 
if p is positive it opens up, if p is negative it opens down.

or

{{x^2}}}%22%22=%22%224py if it opens right or left.
with directrix x=-p and focal point (p,0)
if p is positive it opens right, if negative it opens left.

...and the focal point is 296 units above the directrix.
So it opens upward. The vertex is exactly half-way between the focal point 
and the directrix line.  The focal point is half of 296 or 148 units above 
the vertex.  The focal point is (0,148) and the directrix's equation is
y = -148, and p=+148 

So its equation is

x%5E2%22%22=%22%224%28148%29y 

x%5E2%22%22=%22%22592y

or y%22%22=%22%22expr%281%2F592%29x%5E2



Edwin