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Homework Help: Find the focus and directrix of the parabola !

  1. Dec 6, 2008 #1
    1. The problem statement, all variables and given/known data

    find the focus and directrix of the parabola:
    (y+2)^2 = 16(x-1)

    2. Relevant equations

    (y-k)^2= 4a(x-h)
    focus: ( h+a,k)
    vertex: (h,k)

    3. The attempt at a solution
    k=-2,h=1,a=16/4=4!,
    vertex at (1,-2)
    focus ( 5,-2)
    does that mean that i solved the problem or do i still to do more work to reach the final answer? thanks in advance.
     
  2. jcsd
  3. Dec 6, 2008 #2
    Well, did you find the focus and directrix?
     
  4. Dec 6, 2008 #3
    i think i did , don't you think so ?
     
  5. Dec 6, 2008 #4
    The directrix is a line. You don't have any line equations in your answer.
     
  6. Dec 7, 2008 #5
    directrix : x=h-a
    = 1-4
    = -3 ? how about this, does look right to you, or am i wrong ?
     
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