Question -
Answer -
Given:
The equation is x2┬а=-9y
Here we know that the coefficient of y is negative.
So, the parabola open downwards.
On comparing this equation with x2┬а=-4ay, we get,
-4a = -9
a = -9/-4 = 9/4
Thus, co-ordinates of the focus = (0,-a) = (0, -9/4)
Since, the given equation involves x2,the axis of the parabola is the y-axis.
тИ┤ Theequation of directrix, y = a, then,
y =┬а9/4
Length of latus rectum = 4a = 4(9/4) = 9