What is the directrix (x+2)^2=-(y-1) ?

The directrix (x+2)^2=-(y-1) is y= 5/4

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directrix (x+2)^2=-(y-1)

directrix

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

y = \frac{5}{4}

Solution steps

Rewrite

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

in the standard form:

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

(h, k) = (- 2, 1), 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

(- 2, 1)

y-coordinate

y = 1 - p

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

Refine

y = \frac{5}{4}

y = - 8 x^{2} + 4

3 x^{2} + 6 x - 4

x^{2} + 2 x - 12 y + 37 = 0

2 x^{2} + 16 x + 35

y = 40 x - 5 x^{2}