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anonymous
 one year ago
Derive the equation of the parabola with a focus at (−7, 5) and a directrix of y = −11.
a) f(x) = −one eighth (x − 2)2 + 6
b)f(x) = one eighth (x − 2)2 + 6
c)f(x) = −one eighth (x + 2)2 + 8
d)f(x) = one eighth (x + 2)2 + 8
anonymous
 one year ago
Derive the equation of the parabola with a focus at (−7, 5) and a directrix of y = −11. a) f(x) = −one eighth (x − 2)2 + 6 b)f(x) = one eighth (x − 2)2 + 6 c)f(x) = −one eighth (x + 2)2 + 8 d)f(x) = one eighth (x + 2)2 + 8

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0sec just making sure my numbers work

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0thank you ive narrowed it down to either a or c but i dont know what to do for there

amistre64
 one year ago
Best ResponseYou've already chosen the best response.1one method is to define all points (x,y) that are equidistance from a focus (a,b) and a directrix (in this case y=k)  which is just the point (x,k) (xa)^2 + (yb)^2 = (xx)^2 + (yk)^2

amistre64
 one year ago
Best ResponseYou've already chosen the best response.1(xa)^2 + y^2 2by +b^2 = y^2 2ky +k^2 (xa)^2 2by +b^2 = 2ky +k^2 (xa)^2 +(b^2k^2) = 2by 2ky (xa)^2 +(b^2k^2) = 2(bk)y (xa)^2/(2(bk)) +(b^2k^2)/(2(bk)) = y (xa)^2/(2(bk)) +(b+k)/2 = y

amistre64
 one year ago
Best ResponseYou've already chosen the best response.1none of your options fit ...

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0if you use the formula \[y=a(xh)^2+k \] where P = 7 Q = 5 and R = 11 and where a = \[\frac{ 1 }{ 2Q2R }\] H = P and \[K = \frac{ Q + R }{ 2 }\] you can just plug in the values and solve

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I got that problem too.

amistre64
 one year ago
Best ResponseYou've already chosen the best response.1we know the options are bad or something off, since the parabola opens up its vertex x is the same value as the focus x ... (x+7)^2 is the main part

amistre64
 one year ago
Best ResponseYou've already chosen the best response.1its y value is the average of the focus y and the directrix (511)/2 = 3

amistre64
 one year ago
Best ResponseYou've already chosen the best response.1can you screen shot it?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ya that's why I didn't reply faster... I was wondering if my math was bad or something haha

amistre64
 one year ago
Best ResponseYou've already chosen the best response.1some people tend to post the answers for one with the question of another

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh my i am so sorry i realized the problem

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0two of the questions were switched because those look like they would work for Derive the equation of the parabola with a focus at (2, 4) and a directrix of y = 8

amistre64
 one year ago
Best ResponseYou've already chosen the best response.1never be afraid of your own errors ... they might prove to be correct int he end :)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Using either of the 2 methods posted above with the new data should give you the answer :)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0thank you all so much that was very helpful
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