Results 1 to 4 of 4

Math Help - parabola

  1. #1
    Member
    Joined
    Nov 2008
    Posts
    87

    parabola

    In need to write an equation for the parabola whose vertex is (4, 3), axis of symmetry is y = 3 and the measure of the latus rectum is 4; a > 0. I also need to draw this parabola.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member vincisonfire's Avatar
    Joined
    Oct 2008
    From
    Sainte-Flavie
    Posts
    469
    Thanks
    2
    Awards
    1
    A parabola is the set of all points in the plane equidistant from a given line.
    \sqrt{(y-12)^2+(x-3)^2}=y+4
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,860
    Thanks
    742
    Hello, 14041471!

    Write an equation for the parabola whose vertex is (4, 3),
    axis of symmetry is y = 3 and the measure of the latus rectum is 4; a > 0.
    I also need to draw this parabola.

    You might start with a sketch . . .
    Code:
            |
            |                 *
            |             *
            |          *  :
            |  (4,3) *  p :
          - + - - - o - - o - -
            |      V *    :F
         ---+----------*--:------
            |             * 
            |                 *
            |
    We're expected to know the following . . .

    Since the axis of symmtetry is horizontal, the parabola opens "sideways."
    Since a > 0, the parabola opens to the right.

    The general form is: . (y-k)^2 \:=\:4p(x-h)
    . . where (h,k) is the vertex,
    . . and p is the focal distance (distance from vertex to focus).

    Fact: the length of the latus rectum is 4p.
    . . . . We have: .  4p \:=\:4\quad\Rightarrow\quad p \:=\:1


    Since the vertex is: . (h,k) = (4,3)

    . . the equation is: . (y-3)^2 \;=\;4(x-4)

    Follow Math Help Forum on Facebook and Google+

  4. #4
    Senior Member vincisonfire's Avatar
    Joined
    Oct 2008
    From
    Sainte-Flavie
    Posts
    469
    Thanks
    2
    Awards
    1
    ! Wrong direction for me. May I swap x's and y's?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Parabola
    Posted in the Geometry Forum
    Replies: 2
    Last Post: May 9th 2010, 01:20 AM
  2. parabola
    Posted in the Geometry Forum
    Replies: 1
    Last Post: January 19th 2010, 01:10 AM
  3. Parabola help please
    Posted in the Pre-Calculus Forum
    Replies: 4
    Last Post: January 16th 2010, 07:41 AM
  4. Parabola
    Posted in the Algebra Forum
    Replies: 1
    Last Post: November 25th 2008, 09:07 AM
  5. parabola
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: February 25th 2008, 02:52 PM

Search Tags


/mathhelpforum @mathhelpforum