What is the directrix x=-1/8 y^2 ?

The directrix x=-1/8 y^2 is x=2

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directrix x=-1/8 y^2

directrix

x = - \frac{1}{8} y^{2}

x = 2

Solution steps

Rewrite

x = - \frac{1}{8} y^{2}

in the standard form:

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

(h, k) = (0, 0), p = - 2

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

- p

from the center

(0, 0)

x-coordinate

x = 0 - p

x = 0 - (- 2)

Refine

x = 2

4 x^{2} - y^{2} = 16

x^{2} + y^{2} - 4 x - 4 y = 0

x^{2} = - 4 y

\frac{x ^{2}}{25} + \frac{y ^{2}}{9} = 1

x = y^{2} - 4