Question
Question: The focus of the parabola x<sup>2</sup> = – 16y is...
The focus of the parabola x2 = – 16y is
A
(4, 0)
B
(0, 4)
C
(–4, 0)
D
(0, –4)
Answer
(0, –4)
Explanation
Solution
x2 = –16y
compare with x2 = – 4ay ̃ 4a = 16 ̃ a = 4
\ focus (0, – a) = (0, – 4)