Results 1 to 3 of 3

Math Help - quadratic equations help

  1. #1
    Member
    Joined
    Jan 2008
    Posts
    173

    quadratic equations help

    1)Jorge recorded the number of customers
    y
    that came to his store over a number
    of hours
    x. Does the data represent a
    quadratic function? Explain.

    x
    1 3 5 7 9

    y
    2 5 11 17 23

    2) NASA has a plane that travels in a
    parabola to simulate zero-gravity. Its
    path can be modeled by the equation
    y
    8.6 x 2  560x  24000 where y is
    the altitude in feet and
    x is the time
    since it started the maneuver. What is

    a reasonable domain for this function?


    No; the second differences
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Aug 2009
    Posts
    125
    If they represented a quadratic function, we'd be able to find coefficients a,b,c such that all pairs (x,y) from your table satisfy y=ax^2+bx+c.

    Pair (1,2) gives 2=a+b+c \; \; \; \; \; \;(1)
    Pair (3,5) gives 5=9a+3b+c \; \; \; \; \; (2)
    Pair (5,11) gives 11=25a+5b+c \; \; \; \; \; (3)
    Pair (7,17) gives 17=49a+7b+c \; \; \; \; \; (4)

    Subtracting (1) from (2) we get 3=8a+2b \; \; \; \;(5)
    Subtracting (2) from (3) we get 6=16a+2b \; \; \; \;(6)
    Subtracting (3) from (4) we get 6=24a+2b \; \; \; \;(7)

    Subtracting (5) form (6) we get 3=8a
    Subtracting (6) form (7) we get 0=8a

    This means there's no solution, so the data can't be represented by a quadratic function.

    The second part is illegible for me.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member
    Joined
    Jan 2009
    Posts
    591
    Quote Originally Posted by sri340 View Post



    ...
    a plane that travels in a


    parabola to simulate zero-gravity. Its
    path can be modeled by the equation

    y 8.6 x 2  560x  24000 where y is
    the altitude in feet and x is the time

    since it started the maneuver. What is

    a reasonable domain for this function?
    I cannot understand what the boxes are supposed to be:
    is this the equation:

     y = -8.6 x^2 + 560x + 24000

    Just to make sure, is the time supposed to be in seconds?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. quadratic equations
    Posted in the Algebra Forum
    Replies: 1
    Last Post: December 6th 2010, 05:20 PM
  2. quadratic equations
    Posted in the Algebra Forum
    Replies: 3
    Last Post: August 14th 2010, 06:01 PM
  3. Replies: 1
    Last Post: June 12th 2008, 09:30 PM
  4. quadratic equations
    Posted in the Algebra Forum
    Replies: 3
    Last Post: May 18th 2008, 10:20 AM
  5. Quadratic Equations Help
    Posted in the Algebra Forum
    Replies: 1
    Last Post: January 13th 2008, 08:43 PM

Search Tags


/mathhelpforum @mathhelpforum