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brendizzle17_90

United States
Joined: Apr 23, 2009
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Help with parabolas and ellipses!!!!!

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Find the equation of a parabola with its vertex at the origin if its focus is at (4,0).

Find the center, vertices, and foci for the ellipse: 9x^2+64y^2=576

[Apr 23, 2009 11:48:20 PM]

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pskinner

Joined: Apr 2, 2005
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Re: Help with parabolas and ellipses!!!!!

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Find the equation of a parabola with its vertex at the origin if its focus is at (4,0).

Find the center, vertices, and foci for the ellipse: 9x^2+64y^2=576

The general equation of a parabola is: (x-h)^2=4p(y-k), where (h,k) is the vertex and (h,k+p) is the focus. So, in your case, (h,k)=(0,0) meaning that h=0 and k=0. Further, in your case, (h,k+p)=(0,4), so k+p=4 and since k=0, it must be that p=4.

The equation is (x-0)^2=4*4(y-0), which simplifies to x^2=16y.
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Principal Skinner

[Apr 25, 2009 8:34:21 AM]

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