What is the directrix (x-3)^2=-12y ?

The directrix (x-3)^2=-12y is y=3

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directrix (x-3)^2=-12y

directrix

(x - 3)^{2} = - 12 y

y = 3

Solution steps

Rewrite

(x - 3)^{2} = - 12 y

in the standard form:

4 (- 3) (y - 0) = (x - 3)^{2}

(h, k) = (3, 0), p = - 3

Parabola is symmetric around the y-axis and so the directrix is a line parallel to the x-axis, a distance

- p

from the center

(3, 0)

y-coordinate

y = 0 - p

y = 0 - (- 3)

Refine

y = 3

x^{2} = 10 y

y = 6 x^{2} - 3 x 5

\frac{1}{3} (x + 2)^{2} - 3

x^{2} - 6 x + 5 y = - 34

y^{2} - 8 x = 0