SOLUTION: What is the equation of parabola? if Directrix is y=1 Length of latesrectum is 8, opens downward. (With explanation)

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Question 936635: What is the equation of parabola? if Directrix is y=1 Length of latesrectum is 8, opens downward. (With explanation)

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
the vertex form of a Parabola opening up(a>0) or down(a<0),
y=a%28x-h%29%5E2+%2Bk
where(h,k) is the vertex and x = h is the Line of Symmetry ,
the focus is (h,k + p), With Directrix y = (k - p), a = 1/(4p)
......
recommend starting with a sketch of the curve
Directrix is y=1, Length of latesrectum = 8, p = 2, a =1/(4p)= 1/8
v(0,-1)
y+=+%281%2F8%29x%5E2+-1