SOLUTION: Find the focus, directrix, and focal diameter of the parabola. 9x + 7y2 = 0 focus (x, y) = directrix focal diameter graph:

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: Find the focus, directrix, and focal diameter of the parabola. 9x + 7y2 = 0 focus (x, y) = directrix focal diameter graph:      Log On


   

Question 314229: Find the focus, directrix, and focal diameter of the parabola.
9x + 7y2 = 0
focus (x, y) =
directrix
focal diameter
graph:
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
9x+%2B+7y%5E2+=+0
9x+%2B+7y2+=+0
9x=-7y%5E2
x=-%287%2F9%29y%5E2
Compare to general equation of a parabola,
4px=y%5E2
x=%281%2F%284p%29%29y%5E2
1%2F%284p%29=-7%2F9
4p=-9%2F7
p=-9%2F28
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.
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p is the distance from the focus to the vertex.
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.
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The vertex is at (0,0).
The focus is (-9%2F28,0).
The x coordinate of the directrix is the same distance from the vertex in the opposite direciton.
The directrix is x=9%2F28