Results 1 to 5 of 5

Math Help - Difficult Integral

  1. #1
    Newbie
    Joined
    Feb 2010
    Posts
    2

    Difficult Integral

    I was wondering whether anyone there could explain how to integrate (e^x)/(1+x^2) by parts.

    Many Thanks

    dz
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,236
    Thanks
    28
    Not sure how parts will help here

    Wolfram Mathematica Online Integrator
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor harish21's Avatar
    Joined
    Feb 2010
    From
    Dirty South
    Posts
    1,036
    Thanks
    10
    By parts doesn't seem to work here
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,236
    Thanks
    28
    This is all wrong

    Quote Originally Posted by harish21 View Post
    I used integration by parts this way:

    Let u= 1+{x^2} ; v = e^x

    Then  du= 2x dx ; dv = e^x

    So,  uv - \int v.du

    =  (1+{x^2})(e^x) - \int e^x 2x dx

    =  (1+{x^2})(e^x) - 2e^{x}(x-1)

    For parts you need to make one variable u' and the other v in your case

    Should it not be??

    Let {\color{red}u'= \frac{1}{1+{x^2}}} , v = e^x

    Then  u= \tan^{-1}x , v' = e^x

    Still this will not reduce.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Feb 2010
    Posts
    2
    I agree Pickslides. I tried solving this one using a Matematica powered calculator and it gives me a solution with irrational numbers. Yet I sense that this is not right...


    Here it is:
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. difficult integral
    Posted in the Calculus Forum
    Replies: 2
    Last Post: June 2nd 2010, 03:05 AM
  2. Difficult Integral
    Posted in the Calculus Forum
    Replies: 2
    Last Post: February 12th 2010, 07:57 AM
  3. Difficult integral
    Posted in the Calculus Forum
    Replies: 4
    Last Post: July 22nd 2009, 08:20 AM
  4. another difficult integral
    Posted in the Calculus Forum
    Replies: 10
    Last Post: October 8th 2007, 03:29 PM
  5. difficult integral
    Posted in the Calculus Forum
    Replies: 4
    Last Post: September 3rd 2007, 03:59 PM

Search Tags


/mathhelpforum @mathhelpforum