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anonymous
 one year ago
Find the standard form of the equation of the parabola with a focus at (7, 0) and a directrix at x = 7.
anonymous
 one year ago
Find the standard form of the equation of the parabola with a focus at (7, 0) and a directrix at x = 7.

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0You need to use the combined distance formula for this problem. \[\sqrt{(x_2x_1)+(y_2y_1)}=\sqrt{(y_2+y_1)}\] Plug in the focus of (7, 0) into \[(x_1, y_1)\] of the equation. The equation will now look like this. \[\sqrt{(x_27)+(y_20)}=\sqrt{(y_2+y_1)}\] Lastly, plug in the directrix on the right side of the equation. \[\sqrt{(x_27)+(y_20)}=\sqrt{(y_27)}\] Remove the radicals, distribute the y term binomials. Then, simplify and isolate the x terms. Lastly, isolate the y term.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Oh crap, I'm a total ditz. I forgot to add the most important part of the equation. They're supposed to be squared, so the equation has to look like this. \[\sqrt{(x_2x_1)^2+(y_2y_1)^2}=\sqrt{(y_2+y_1)^2}\]

DanJS
 one year ago
Best ResponseYou've already chosen the best response.0Here is a thing i just found that may help too.. http://hotmath.com/hotmath_help/topics/findingtheequationofaparabolagivenfocusanddirectrix.html

DanJS
 one year ago
Best ResponseYou've already chosen the best response.0Each point on the parabola is always equal distance from the focus and the directrix... that is why you set up 2 distance formulas and equate them
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