Results 1 to 2 of 2

Math Help - Function problem

  1. #1
    Member
    Joined
    Apr 2008
    Posts
    107

    Function problem

    A rectangle has a vertex on the graph of y = 9 - x^2, one in the origin, one in the positive side of the x - axis, and the fourth one on the positive side of the y - axis.

    * express the area of the rectangle as a function of x
    * what is the domain? ( i can prob get this when i know how to do the area one)
    * wat is the area of the rectangle when x = 1.5?

    thanks for your help
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,682
    Thanks
    614
    Hello, NeedHelp18!

    Did you make a sketch?


    A rectangle has a vertex on the graph of y \:= \:9 - x^2,
    one at the origin, one on the positive x - axis, and the fourth one on the positive y - axis.

    (a) Express the area of the rectangle as a function of x.
    Code:
                  |
                  *9
              *   |   *
           *      + - - -*
         *        |::::::| *
        *         |::::::|y *
                  |::::::|
      -*----------+------+---*-
                  |   x      3
    The area of the rectangle is: . A \:=\:xy\text{, where }y \:=\:9-x^2

    Therefore: . A(x) \;=\;x(9-x^2)




    (b) What is the domain?
    The domain is: . 0 \,\leq\, x \,\leq\,3



    (c) What is the area of the rectangle when x = 1.5?
    A(1.5) \;=\;1.5(9 - 1.5^2) \;=\;10.125

    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 20
    Last Post: November 27th 2012, 05:28 AM
  2. Replies: 6
    Last Post: August 13th 2010, 01:03 AM
  3. 1 Word problem and 1 function problem
    Posted in the Algebra Forum
    Replies: 8
    Last Post: April 21st 2010, 08:01 AM
  4. Greatest integer function (=step function) problem
    Posted in the Math Topics Forum
    Replies: 5
    Last Post: June 7th 2009, 01:43 PM
  5. Function within a function problem
    Posted in the Calculus Forum
    Replies: 10
    Last Post: April 26th 2009, 03:49 PM

Search Tags


/mathhelpforum @mathhelpforum