Find the focus directrix focal diameter vertex and axis of s
Find the focus, directrix, focal diameter, vertex and axis of symmetry for the parabola
68(y2)=(x+7)^2
Solution
Solution: Equation of the parabola 68(y2) = (x+7)^2.
Comparing this equation with the standard equation of parabola 4a(yk) = (x-h)^2, we get h=-7, k=2 and 4a = 68
or a = 17.
We know that focus (0,a) = (0, 17) or (x+7, y-2) = (0, 17) or x =-7, y=19.
Thus Focus = (-7, 19).
Equation of directrix is (y-k) = -a or (y-2) =-17 or y =-17+2 =-15
Vertex (h, k) = (2,-7).
Axis of symmetry is x+7=0 or x = -7.
Focal diameter = 4a = 4 (17).
Thus Focal diameter = 68. Ans
And directrix is y = -15.
