Derive the equation of the parabola with a focus at (2, 4) and a directrix of y = 8.

Question

anonymous · Answer

Derive the equation of the parabola with a focus at (2, −1) and a directrix of y = −1/2

accessdenied · Answer

Do you know the definition of a parabola in terms of its focus and directrix?

anonymous · Answer

no i just got this homework that is due in 2 days... my teacher told us to just figure it out

accessdenied · Answer

That's a bit over-the-top for something like this that is quite difficult to grasp...

But, if you bear with me a moment, I will explain the concept.  It isn't terribly difficult once you understand how it works.

anonymous · Answer

okay, thank you!

accessdenied · Answer

A parabola is defined to be the set of points that are an equal distance from the line (directrix) and the point (focus).

accessdenied · Answer

So, if you can imagine the shape (which I will sketch):
|dw:1395090396587:dw|