What is the directrix of the parabola defined by `(1)/(4)(y + 3) = (x − 2)^2`? A. `y = -(49)/(16)` B. `x = -(49)/(16)` C. `y = (47)/(16)` D. `x = (47)/(16)`

Question

asked Feb 24, 2019 136k views

2 Answers

Crasic · Answer 1 · 2019-03-01T22:00:36+0000

Answer:

A.
y=-(49)/(16)

Explanation:

Since, the directrix of a parabola
(x - h)^2 = 4p (y - k) is,

y = k - p

Here, the given parabola,

(1)/(4)(y+3)=(x-2)^2

By comparing,

We get,

k = - 3,

$4p=(1)/(4)\implies p=(1)/(16)$

Hence, the directrix of the given parabola is,

y=-3-(1)/(16)

y=(-48-1)/(16)

$\implies y = -(49)/(16)$

Option 'A' is correct.