What is the directrix-x^2-2x-1 ?

The directrix-x^2-2x-1 is y= 1/4

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directrix-x^2-2x-1

directrix

- x^{2} - 2 x - 1

y = \frac{1}{4}

Solution steps

Rewrite

y = - x^{2} - 2 x - 1

in the standard form

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

(h, k) = (- 1, 0), p = - \frac{1}{4}

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

(- 1, 0)

y-coordinate

y = 0 - p

y = 0 - (- \frac{1}{4})

Refine

y = \frac{1}{4}

y + 3 x^{2} = 0

y^{2} - 8 x - 8 y + 24 = 0

y = + x^{2} - 4 x - 32

x^{2} + 2 x + 2

y = x^{2} - 2 x - 15