Results 1 to 3 of 3

Math Help - h

  1. #1
    Junior Member
    Joined
    Sep 2007
    Posts
    29

    h

    \int_{-3}^{3} |x+2|...is there something special you have to do with these when they are absolute value because I'm not getting the correct answer

    I integrate it to be x^2 /2 +2xthen plug the numbers in and dont get the proper answer of 13
    Last edited by jst706; September 25th 2007 at 06:34 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Global Moderator

    Joined
    Nov 2005
    From
    New York City
    Posts
    10,616
    Thanks
    9
    Quote Originally Posted by jst706 View Post
    \int_{-3}^{3} |x+2|...is there something special you have to do with these when they are absolute value because I'm not getting the correct answer

    I integrate it to be x^2 /2 +2xthen plug the numbers in and dont get the proper answer of 13
    \int_{-3}^{-2}|x+2|dx + \int_{-2}^3 |x+2|dx

    \int_{-3}^{-2}-(x+2)dx + \int_{-2}^3 (x+2) dx
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,676
    Thanks
    608
    Hello, jst706!

    \int_{-3}^{3}|x+2|\,dx . Is there something special you have to do with these
    . . . . when there are absolute value? . . . . yes
    You might graph the function: . y \:=\:|x+2|

    Code:
                            |           *
                            |         *
                            |       *::
          *                 |     *::::
            *               |   *::::::
              *             | *::::::::
                *           *::::::::::
                ::*       *:|::::::::::
                ::::*   *:::|::::::::::
          - - - + - - * - - + - - - - + - -
               -3    -2     |         3

    The area is: . \int^{-2}_{-3}(-x - 2)\,dx + \int^3_{-2}(x + 2)\,dx

    Follow Math Help Forum on Facebook and Google+


/mathhelpforum @mathhelpforum