What is the standard form of the equation of the parabola with a directrix at x=-2 and a focus at (-3,3)?

1 Answer
Aug 21, 2016

(y-3)^2=-(2x+5)(y3)2=(2x+5), is the reqd. eqn. of Parabola.

Explanation:

Let F(-3,3)F(3,3) be the Focus, and, d : x+2=0d:x+2=0 the Directrix of the

reqd. Parabola denoted by SS.

It is known from the Geometry, that, if P(x,y) in SP(x,y)S, then, the bot-

distance btwn. the pt. PP & dd is the same as the distance btwn.

the pts. FF & PP.

This Property of Parabola is known as the Focus Directrix Property

of Parabola.

:. |x+2|=sqrt{(x+3)^2+(y-3)^2}

:. (y-3)^2+(x+3)^2-(x+2)^2=0

:. (y-3)^2=-(2x+5), is the reqd. eqn. of Parabola.