If the equation of the parabola is x2 = - 8y, the equation of the directix and length of latus rectum, respectively are

Question

If the equation of the parabola is x2 = - 8y, the equation of the directix and length of latus rectum, respectively are (A) y = 3 ,4 (B) y = -2,4 (C) y = 2, 8 (D) y = -2 ,8

Tardigrade Admin · Accepted Answer

Comparing the given equation with standard form x2 = -4ay , we get a = 2. Therefore, the equation of directrix is y = 2 and the length of the latus rectum is 4a, i.e., 8.

Q. If the equation of the parabola is $x^{2} = - 8 y$ , the equation of the directix and length of latus rectum, respectively are

$y = 3, 4$

$y = - 2, 4$

$y = 2, 8$

$y = - 2, 8$

Comparing the given equation with standard form $x^{2} = - 4 a y$ , we get $a = 2$ .
Therefore, the equation of directrix is $y = 2$ and the length of the latus rectum is $4 a$ , i.e., $8$ .

Q. If the equation of the parabola is x2=−8y, the equation of the directix and length of latus rectum, respectively are

y=3,4

y=−2,4

y=2,8

y=−2,8