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anonymous
 one year ago
Find the standard form of the equation of the parabola with a focus at (0, 9) and a directrix y = 9.
anonymous
 one year ago
Find the standard form of the equation of the parabola with a focus at (0, 9) and a directrix y = 9.

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0i know how to do it when they give me x but they gave my y instead

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1dw:1435907166360:dw ok first lets just plug what we have, then we will see what formula to use.

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1The graph is sort of bad, but we can fix that after. We will have to use the equation \[(xh)^2=4p(yk)\] look familiar, so far so good?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0we can plug in h k and y

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1Ok so lets just write out what we have so far, h = 0 k = 9 Any idea what p might be? This is a bit tricky.

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1Well, let me ask you a question, what way is the parabola, is it opening up, down, left, right what's going on?

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1Also, we can figure out the vertex right away, as it's the same distance from vertex to directrix and vertex to focus. So it's the middle point between the focus and directrix.

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1dw:1435908052023:dw right?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so the directrix would be 0?

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1No no, we're given the directrix, it's y = 9, but the vertex is (0,0) as it's the middle point between the directrix and the focus, where we were given the focus (0,9)

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1Ok cool, so our graph looks something like this dw:1435908205110:dw now we can write the equation

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1Because it cannot cross the directrix, so if it was the other way, this would happen dw:1435908273394:dw and it can't cross the directrix!

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1dw:1435908337698:dw

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1Nope, not 10, but 9, sorry about the picture, I just put 10 there to give an idea of the scale.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh ok yea i see the 9 now

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1Alright cool, now just plug in all the value and standard form is in the following: \[x=ay^2+by+c\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0but in the answer choice the closest thing to 9 for p is 9, would 9 be right?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh wait isnt it 1/4p?

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1May I see your answer choices actually

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0y = 1/9x^2 y2 = 36x y = 1/36x y2 = 9x

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1Ok I see so it wants it in \[y = \frac{ 1 }{ 4 p}(xh)^2+k\] form

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1That looks good to me

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ok thank you! could you help me with one more but ill make a new post so i can give u another medal

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1That should be x^2 though

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0yea its x^2 i forgot to put the ^2

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1\[y = \frac{ 1 }{ 36 }x^2\] so just in case, that is your final answer
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