Results 1 to 2 of 2

Math Help - Stuck on integration problem please help

  1. #1
    Newbie
    Joined
    Nov 2008
    Posts
    20

    Stuck on integration problem please help

    evaluate the integral by reversing the order of integration
    *please forgive me I don't know how to show integrals on here

    this is a double integral
    integral from 0 to 1 integral from 6y to 6 of e^x^2 dxdy
    I changed the bounds to
    x is between 0 and 6
    y is between x/6 and 1
    i get stuck on the integral between 0and 6 e^x^2(1-x/6)dx
    I tried substitution but I wind up with e^u/(2x)-e^u/12 which doesn't work
    How do I integrate this?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor Mathstud28's Avatar
    Joined
    Mar 2008
    From
    Pennsylvania
    Posts
    3,641
    Quote Originally Posted by koalamath View Post
    evaluate the integral by reversing the order of integration
    *please forgive me I don't know how to show integrals on here

    this is a double integral
    integral from 0 to 1 integral from 6y to 6 of e^x^2 dxdy
    I changed the bounds to
    x is between 0 and 6
    y is between x/6 and 1
    i get stuck on the integral between 0and 6 e^x^2(1-x/6)dx
    I tried substitution but I wind up with e^u/(2x)-e^u/12 which doesn't work
    How do I integrate this?
    We have by the bounds that 0\leqslant{y}\leqslant{1} and 6y\leqslant{x}\leqslant{6}. The second inequality is equivalent to y\leqslant\frac{x}{6}\leqslant{1}. So stringing our inequalities toegether gives

    0\leqslant{y}\leqslant\frac{x}{6}\leqslant{1}

    From there it is obvious that

    \int_0^1\int_{6y}^{6}f(x,y)dx~dy=\int_0^6\int_0^{\  frac{x}{6}}f(x,y)dy~dx
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Integration problem, stuck, not sure
    Posted in the Calculus Forum
    Replies: 4
    Last Post: July 10th 2011, 06:15 PM
  2. [SOLVED] Stuck on an Integration
    Posted in the Calculus Forum
    Replies: 2
    Last Post: January 1st 2011, 06:18 AM
  3. Integration---I'm stuck!
    Posted in the Calculus Forum
    Replies: 1
    Last Post: September 13th 2009, 10:43 PM
  4. Stuck on some integration
    Posted in the Calculus Forum
    Replies: 8
    Last Post: December 28th 2008, 03:53 AM
  5. stuck on integration
    Posted in the Calculus Forum
    Replies: 4
    Last Post: June 6th 2008, 07:45 PM

Search Tags


/mathhelpforum @mathhelpforum