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Math Help - parabolas

  1. #1
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    parabolas

    find the vertex, focus, and directrix of the parabola and sketch its graph

    x + y^2 = 0
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  2. #2
    MHF Contributor harish21's Avatar
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    Quote Originally Posted by kenzie103109 View Post
    find the vertex, focus, and directrix of the parabola and sketch its graph

    x + y^2 = 0
    The equation of your parabola would be :

    (y-k)^2=4p(x-h)

    where (h,k) is the vertex

    Put your given equation in the above form. This should be explained in your book. Show your work if you have any problems.
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  3. #3
    Super Member bigwave's Avatar
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    Cool

    Quote Originally Posted by kenzie103109 View Post
    find the vertex, focus, and directrix of the parabola and sketch its graph

    x + y^2 = 0
    as mentioned since h=0 and k=0

    then you have a vertex at V(0.0)

    so now we have the equation of y^2 = 4ax here 4a= -1 so a = -\frac{1}{4}

    Focus at (a,0) so F(-\frac{1}{4},0)

    Directix at x = -a so x =\frac{1}{4} is the Directix

    note some books use a versus p as the variable
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