Question

Yung is designing a flashlight that uses a parabolic reflecting mirror and a light source. The shape of the mirror can be modeled by x^2=8y, where x and y are measured in inches. What is the focus point of the flashlight?

A. (-2,0)
B. (0,-2)
C. (0, 2)
D. (2,0)

Answer 1

C

Explanation:

Answer 2

The general form for a parabolic dish is:

y=x^2/(4f), where f=focus' y coordinate when x=0

So if you are given the equation:

8y=x^2, you need only to rearrange it to the form y=x^2/(4f)

y=x^2/8

Since 8=4f, f=2 inches and the focal point of course (0,2)