How do you find the vertex, focus, and directrix of the parabola (x+3)+(y-2)^2=0(x+3)+(y2)2=0?

1 Answer
Jul 1, 2018

Vertex is at (-3,2)(3,2), directrix is x = - 2.75x=2.75 and
focus is at
(-3.25,2)(3.25,2)

Explanation:

(x+3)+(y-2)^2=0 or (y-2)^2=-(x+3) (x+3)+(y2)2=0or(y2)2=(x+3) or

(y-2)^2=-4*0.25(x+3) (y2)2=40.25(x+3) The equation of horizontal

parabola opening left is

(y-k)^2 = -4p(x-h) ; h=-3 ,k=2 , p = 0.25 ; h ,k(yk)2=4p(xh);h=3,k=2,p=0.25;h,k

being vertex .Therefore vertex is at (-3,2)(3,2)

Distance between focus and vertex is p=0.25p=0.25

Here the directrix is at right of the vertex. Therefore the

equation of directrix is x=(-3+0.25) or x = - 2.75x=(3+0.25)orx=2.75

Vertex is at midway between focus and directrix. Therefore,

focus is at (-3-0.25),2 or (-3.25,2)(30.25),2or(3.25,2)

graph{(x+3)+(y-2)^2=0 [-10, 10, -5, 5]} [Ans]