# Parabola problem

• Jul 11th 2009, 02:56 PM
Kevin Green
Parabola problem
I'm trying to figure out what the heck I'm supposed to do with this:

x^2=8y.

I'm supposed to solve for vertex, focus, and directx... how do I put this into the y=ax^2+bc+c form??
• Jul 11th 2009, 03:09 PM
skeeter
Quote:

Originally Posted by Kevin Green
I'm trying to figure out what the heck I'm supposed to do with this:

x^2=8y.

I'm supposed to solve for vertex, focus, and directx... how do I put this into the y=ax^2+bc+c form?? ... divide both sides by 8 ; a = 1/8 , b = 0, c = 0

.
• Jul 11th 2009, 03:31 PM
Kevin Green
Thank you.... where do I go from here? The math book I have does a horrible job describing this whole matter. :(
• Jul 11th 2009, 04:08 PM
skeeter
• Jul 11th 2009, 05:08 PM
yeongil
Quote:

Originally Posted by Kevin Green
I'm trying to figure out what the heck I'm supposed to do with this:

x^2=8y.

I'm supposed to solve for vertex, focus, and directx... how do I put this into the y=ax^2+bc+c form??

Parabolas can also be expressed in this form:
$(x - h)^2 = 4p(y - k)$ or $(y - k)^2 = 4p(x - h)$.
The first is a parabola that opens upward or downward, and the second is a parabola that opens left or right. Sometimes this form is preferred because you can see what the vertex is.

$x^2=8y$