Question

Find the vertex, value of p, axis of symmetry, focus, and directrix of the parabola. y-4=-1/2(x-8)^2.
Help Please.

Answer 1

y - 4 = -1/2(x - 8)^2

y = -1/2(x - 8)² + 4

Vertex (8,4) <=x value opposite of inside parentheses and outside number for y

a = -1/2

a = 1/(4p)

-1. . . 1
---- = -----
2 . . .4p

-4p = 2

p = -1/2

Focus (8,3.5) <=vertex plus p value onto y

Directrix: y = 4.5 vertex y value - p which is - (-.5) or + .5

Axis of Symmetry: x = 8 <= x value of vertex

I hope that helps!! :-)

Answer 2

thank you :)

Answer 3

Welcome!