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anonymous

  • one year ago

directrix =-2 and focus is at (4,3) find equation and the vertex

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  1. anonymous
    • one year ago
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    @freckles

  2. jdoe0001
    • one year ago
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    x=-2?

  3. anonymous
    • one year ago
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    vertex = -2

  4. jdoe0001
    • one year ago
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    -2? so..hmmm shouldn't it be an ordered pair? 0,-2? -2,0?

  5. anonymous
    • one year ago
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    actually i think the directrix is -2

  6. jdoe0001
    • one year ago
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    well then, you found it already then =)

  7. anonymous
    • one year ago
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    i need help finding the eq and vertex

  8. jdoe0001
    • one year ago
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    well, the directrix should have an equation x = -2? y = -2?

  9. anonymous
    • one year ago
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    x = -2

  10. jdoe0001
    • one year ago
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    |dw:1442276451048:dw| so.. where do you think the vertex would be?

  11. anonymous
    • one year ago
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    1,3

  12. anonymous
    • one year ago
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    how do i find equation

  13. jdoe0001
    • one year ago
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    well, right.. 1,3 is correct.. the equation is ahemm notice the distance from the vertex to either, the focus or directrix, is 3 units thus p = 3 and it's also a horizontal parabola thus \(\bf \begin{array}{llll} (y-{\color{blue}{ k}})^2=4{\color{purple}{ p}}(x-{\color{brown}{ h}}) \\ (x-{\color{brown}{ h}})^2=4{\color{purple}{ p}}(y-{\color{blue}{ k}})\\ \end{array} \qquad \begin{array}{llll} vertex\ ({\color{brown}{ h}},{\color{blue}{ k}})\\ {\color{purple}{ p}}=\textit{distance from vertex to }\\ \qquad \textit{ focus or directrix} \end{array}\qquad thus \\ \quad \\ \begin{array}{llll} (y-{\color{blue}{ 3}})^2=4{\color{purple}{ (3)}}(x-{\color{brown}{ 1}}) \\ \end{array} \qquad \begin{array}{llll} vertex\ ({\color{brown}{ 1}},{\color{blue}{ 3}})\\ {\color{purple}{ p}}=\textit{distance from vertex to }\\ \qquad \textit{ focus or directrix} \end{array}\)

  14. jdoe0001
    • one year ago
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    because is a horizontal parabola, the "y" is the squared variable

  15. jdoe0001
    • one year ago
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    would... but need to dash in 1 sec :|

  16. anonymous
    • one year ago
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    okay

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