Question
Find the directrix of the parabola defined by the equation (x-6)^2 = 20(y+2)(x−6)
2
=20(y+2).
2
=20(y+2).
Answers
oobleck
recall that the parabola
x^2 = 4py
has as its directrix the line y = -p
Your parabola (without the annoying repetition) is
(x-6)^2 = 20(y+2)
so p = 5, so since the vertex is at (6,-2) the directrix is the line
y = -2-5 = -7
x^2 = 4py
has as its directrix the line y = -p
Your parabola (without the annoying repetition) is
(x-6)^2 = 20(y+2)
so p = 5, so since the vertex is at (6,-2) the directrix is the line
y = -2-5 = -7