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Thread: Parabola help

  1. #1
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    Parabola help

    X=1/2 (y+3)^2 +1

    Center I got (1,-3). And p= 1/2? Or no? And focus= (1 1/2,-3) and directrix of x= 1/2? Or is p wrong and I messed everything up?
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  2. #2
    MHF Contributor MarkFL's Avatar
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    Re: Parabola help

    The focus and directrix are correct, but p = 1. Oh, and the term is vertex, not center.
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  3. #3
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    Re: Parabola help

    Please explain how p=1. I don't know how I got correct focus and directrix if i used 1/2 as p. I believe you are correct just not sure how. I am terrible at math
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  4. #4
    MHF Contributor MarkFL's Avatar
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    Re: Parabola help

    p = 2f = 2(1/2) = 1. Perhaps you are confusing p and f?
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    Re: Parabola help

    Sorry still don't follow. What is f? What does it stand for?
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  6. #6
    MHF Contributor MarkFL's Avatar
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    Re: Parabola help

    f is the distance between the focus and the vertex.
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  7. #7
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    Re: Parabola help

    That is what I thought but if p=1 wouldn't focus be (2,-3) and directrix be x=0?
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  8. #8
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    Re: Parabola help

    Sorry nevermind. I just don't know how I got correct focus and directrix using p=1/2. I thought if p=1 then equation would be
    X=1/4 (y+3)^2+1
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