Derive the equation of the parabola with a focus at (0, 1) and a directrix of y = −1. (2 points) a. f(x) = − one fourth x2 b. f(x) = one fourth x2 c. f(x) = −4x2 d. f(x) = 4x2

The vertex is at (0, 0), halfway between the focus and directrix. This distance from focus to vertex (p) is 1 unit. The equation can be written as
  f(x) = 1/(4p)(x -0)²
or
  f(x) = (1/4)x²

This corresponds to the second selection,
  B. f(x) = (1/4)x²