Results 1 to 2 of 2

Math Help - Washer problem

  1. #1
    Junior Member
    Joined
    Sep 2008
    Posts
    27

    Washer problem

    Okay, after all the help ive gotten today i was able to do most of my homework. But one problem has me stumped.

    A rectangle is formed by the points (2,0) (12,0) (2,2.6) and (12,2.6). This rectangle is revolved around the y-axis.

    So I set up a washer problem whereby I say

    (outside washer) INTEGRAL of: (pi)(r^2)dy
    (inside washer) INTEGRAL of: (pi)(r^2)dy
    r for the outside washer = 12
    r for the inside washer = 2

    INTEGRAL of: 144pi dy - INTEGRAL of 4pi dy
    both evaluated from 0-2.6
    And I get an answer of 1143.539726 but that is wrong.
    What am i doing wrong? Not having an equation is messing me up.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    12,132
    Thanks
    1012
    your solution is fine ... maybe it's supposed to be in terms of \pi ?

    V = 364\pi

    other than that, all I can suggest is recheck the problem.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Washer problem, maybe?
    Posted in the Calculus Forum
    Replies: 0
    Last Post: November 21st 2009, 10:01 AM
  2. washer method
    Posted in the Calculus Forum
    Replies: 2
    Last Post: April 23rd 2009, 05:48 AM
  3. Disk/Washer Method Problem
    Posted in the Calculus Forum
    Replies: 1
    Last Post: December 1st 2008, 02:58 PM
  4. Washer method
    Posted in the Calculus Forum
    Replies: 3
    Last Post: November 19th 2008, 05:13 PM
  5. "Washer" problem
    Posted in the Calculus Forum
    Replies: 1
    Last Post: December 11th 2007, 06:56 PM

Search Tags


/mathhelpforum @mathhelpforum