Results 1 to 4 of 4

Math Help - finding the limits in double integration

  1. #1
    Newbie
    Joined
    Dec 2012
    From
    United Kingdom
    Posts
    5

    finding the limits in double integration

    Sketch the region, R, in the first quadrant bounded by
    y=7x, y=4=(x/2), y=(x-2)^2

    evaluate, SSr(x+y)dxdy,

    what is the limits, and how do i work it out, i have sketch the region already,

    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Mar 2010
    Posts
    993
    Thanks
    244

    Re: finding the limits in double integration

    In this case you have to break the integral up into three integrals - depending on what is the border of the region on the left and right.

    top region: x goes from \frac{y}{7} to +\sqrt{y}+2
    middle region: x goes from -\sqrt{y}+2 to +\sqrt{y}+2
    bottom region: x goes from -\sqrt{y}+2 to 2y

    It might be easier to integrate the other way (dydx instead of dxdy).

    - Hollywood
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor
    Prove It's Avatar
    Joined
    Aug 2008
    Posts
    11,592
    Thanks
    1445

    Re: finding the limits in double integration

    Quote Originally Posted by newkidz View Post
    Sketch the region, R, in the first quadrant bounded by
    y=7x, y=4=(x/2), y=(x-2)^2

    evaluate, SSr(x+y)dxdy,

    what is the limits, and how do i work it out, i have sketch the region already,
    You have a typo, is your second bound y = 4 + (x/2) or y = 4 - (x/2)? Until we know this, we can not say what the bounds of integration are.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Super Member
    Joined
    Mar 2010
    Posts
    993
    Thanks
    244

    Re: finding the limits in double integration

    Quote Originally Posted by Prove It View Post
    You have a typo, is your second bound y = 4 + (x/2) or y = 4 - (x/2)? Until we know this, we can not say what the bounds of integration are.
    Good point! I read it as y=4 and y=x/2 (and y=7x and y=(x-2)^2, so there are 4 curves in the x-y plane) and I based my answer on that.

    - Hollywood
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Help finding these limits of integration?
    Posted in the Calculus Forum
    Replies: 3
    Last Post: November 16th 2011, 11:28 PM
  2. Reversing double integration limits
    Posted in the Calculus Forum
    Replies: 12
    Last Post: February 25th 2011, 05:48 PM
  3. limits of double integration
    Posted in the Calculus Forum
    Replies: 1
    Last Post: October 11th 2009, 03:50 PM
  4. finding the limits of double integral
    Posted in the Calculus Forum
    Replies: 6
    Last Post: October 10th 2009, 08:23 PM
  5. Double integration: limits
    Posted in the Calculus Forum
    Replies: 2
    Last Post: May 8th 2008, 07:28 PM

Search Tags


/mathhelpforum @mathhelpforum