Question

What is an equation of a parabola with a vertex at the origin and directrix x = 4.75?

A. y = –one over nineteenx2

B. y = one over nineteenx2

C. x = –one over nineteeny2

D. x = one over nineteeny2

Answer 1

The equation of a parabola with a vertex at the origin and a directrix at x = 4.75 is in the form x = -1/(4p)y^2, where p is the distance from the vertex to the focus (which is also the distance from the vertex to the directrix).

In this case, p = 4.75 (since the directrix is at x = 4.75). So, the equation of the parabola would be x = -1/(4*4.75)y^2.

Simplifying, we get:

x = -1/19y^2

So, the correct answer is:

A. y = –1/19x^2