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sloppycanada

  • one year ago

Parabola Help How do I find the focus just from looking at a graph? In the link below I have a screenshot of a parabola. I think the Focus is (4,0) http://gyazo.com/ed37c6ae63a875a4d4a05b6fbc6d9591 In addition to that, in the following graph, is the directrix of parabola? I think it is x = -5 http://gyazo.com/7377f7108554c08443c93d78957df350

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  1. ganeshie8
    • one year ago
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    By definition of parabola, the distances from any-point-on-the-parabola to the directrix and focus are equal : |dw:1435565663127:dw|

  2. sloppycanada
    • one year ago
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    Oh okay, so for the first one the correct answer would be (5,0)?

  3. ganeshie8
    • one year ago
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    Yep

  4. sloppycanada
    • one year ago
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    Am I right on the second one?

  5. ganeshie8
    • one year ago
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    x = -5 is the equation of directrix line, yes

  6. ganeshie8
    • one year ago
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    |dw:1435566256822:dw|

  7. sloppycanada
    • one year ago
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    Write the equation of a parabola with a vertex at (0, 0) and a directrix y = -1. What is the equation of the parabola with a focus at (0, -5) and directrix y = 5? Write the equation of a parabola with a vertex at (5, 2) and a directrix y = 1.|dw:1435566317796:dw|

  8. sloppycanada
    • one year ago
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    @ganeshie8 Am I right? I'm not sure what the medal means.

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