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

The directrix y=2x^2-3 is y=-25/8

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directrix y=2x^2-3

directrix

y = 2 x^{2} - 3

y = - \frac{25}{8}

Solution steps

Rewrite

y = 2 x^{2} - 3

in the standard form:

4 \cdot \frac{1}{8} (y - (- 3)) = (x - 0)^{2}

(h, k) = (0, - 3), p = \frac{1}{8}

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

(0, - 3)

y-coordinate

y = - 3 - p

y = - 3 - \frac{1}{8}

Refine

y = - \frac{25}{8}

(y + 1)^{2} = 16 (x - 3)

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

y = 2 x^{2} - 7 x - 3

x^{2} + 5 x - 7

y^{2} - 6 y - 8 x - 23 = 0