Results 1 to 2 of 2

Math Help - Volumes of Revolution

  1. #1
    Newbie
    Joined
    Nov 2008
    Posts
    8

    Question Volumes of Revolution

    I have this question which is rather interesting and quite hard IMO.

    I have to find the volumes of revolution generated by the regions A and B when they are each rotated about: the x axis and the y axis

    If the equation was from a to b,then it means I need to find the volume of revolution for:

    • x = a to b, rotated around the x axis, which would be:
    • y = a to b, roated around the y axis, which would be:


    are those right?

    I also have to find this though and this is what I need help with:

    • x = a to b, rotated around the y axis
    • y = a to b, roated around the x axis

    I dont know what to do for this though
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Aug 2008
    Posts
    903
    Quote Originally Posted by jhomie View Post
    I have this question which is rather interesting and quite hard IMO.

    I have to find the volumes of revolution generated by the regions A and B when they are each rotated about: the x axis and the y axis

    If the equation was from a to b,then it means I need to find the volume of revolution for:

    • x = a to b, rotated around the x axis, which would be:
    • y = a to b, roated around the y axis, which would be:

    Those are correct. The other two involve volumes using cylindrical shells which have the formula V=2\pi\int_a^b xf(x)dx or 2\pi\int_a^b yg(y)dy so:

    V_y=2\pi\int_a^b x^{n+1}dx

    V_x=2\pi\int_a^b y^{1+1/n}dy
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Volumes of Revolution
    Posted in the Calculus Forum
    Replies: 3
    Last Post: December 13th 2010, 03:31 PM
  2. Replies: 6
    Last Post: February 11th 2010, 07:08 PM
  3. Volumes of Revolution
    Posted in the Calculus Forum
    Replies: 7
    Last Post: February 1st 2010, 06:23 PM
  4. volumes of revolution
    Posted in the Calculus Forum
    Replies: 3
    Last Post: May 17th 2009, 01:15 PM
  5. Volumes of Revolution
    Posted in the Calculus Forum
    Replies: 5
    Last Post: February 26th 2009, 10:57 PM

Search Tags


/mathhelpforum @mathhelpforum