Results 1 to 4 of 4

Math Help - exponential integral

  1. #1
    Member
    Joined
    Nov 2005
    Posts
    172

    exponential integral

    not quite sure how to do this one:

    \int^2_1 e^{lnu}\frac{1}{u}du
    Follow Math Help Forum on Facebook and Google+

  2. #2
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by viet View Post
    not quite sure how to do this one:

    \int^2_1 e^{lnu}\frac{1}{u}du
    substitution. let t = ln(u)
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Global Moderator

    Joined
    Nov 2005
    From
    New York City
    Posts
    10,616
    Thanks
    10
    Note,
    e^{\ln u}=u

    So,
    e^{\ln u}\cdot \frac{1}{u} = \frac{u}{u}=1
    Follow Math Help Forum on Facebook and Google+

  4. #4
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by ThePerfectHacker View Post
    Note,
    e^{\ln u}=u

    So,
    e^{\ln u}\cdot \frac{1}{u} = \frac{u}{u}=1
    yeah, i missed that. thanks
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Exponential Integral
    Posted in the Calculus Forum
    Replies: 9
    Last Post: June 2nd 2011, 10:29 AM
  2. exponential integral
    Posted in the Calculus Forum
    Replies: 6
    Last Post: July 18th 2010, 06:44 AM
  3. Integral of an exponential
    Posted in the Calculus Forum
    Replies: 5
    Last Post: February 2nd 2010, 04:55 AM
  4. exponential integral
    Posted in the Calculus Forum
    Replies: 5
    Last Post: February 22nd 2009, 05:09 AM
  5. exponential integral
    Posted in the Calculus Forum
    Replies: 3
    Last Post: March 17th 2008, 03:57 PM

Search Tags


/mathhelpforum @mathhelpforum