Question 588579: 9x2 +14y = 0
Find focus, directrix, and focal diameter
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! 9x2 +14y = 0
Find focus, directrix, and focal diameter.
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Standard form of equation for a parabola that opens downwards: (x-h)^2=-4p(y-k), (h,k) being the (x,y) coordinates of the vertex.
For given equation: 9x^2+14y=0
9x^2=-14y
x^2=(-14/9)y
vertex: (0,0)
axis of symmetry: y-axis or x=0
4p=14/9
p=14/36=7/18
focus: (0,0-p)=(0,-7/18)
directrix: y=7/18
focal diameter also known as focal width=4p=14/9
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