# Question #46d00

##### 1 Answer

Oct 30, 2017

The distance between any point,

The distance any point,

Because the definition of the parabola requires that these two distances be equal, we can set the right sides of both equations equal:

Square both sides of the equation and convert the -- to a +:

Expand the squares:

Combine like terms:

Divide both sides by 4:

The derivation is complete.