1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Evaulating this Integral

  1. Jan 22, 2012 #1
    1. The problem statement, all variables and given/known data

    http://img528.imageshack.us/img528/356/hwhelp.png [Broken]

    2. Relevant equations

    http://img407.imageshack.us/img407/3696/uanddu.png [Broken]

    3. The attempt at a solution
    This is the answer I got. I was wondering how du replaces the circled part of the question.

    http://img546.imageshack.us/img546/8975/hwanswer.png [Broken]
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Jan 22, 2012 #2
    I just came up with this information now. Is it right?

    http://img851.imageshack.us/img851/3763/uandupart2.png [Broken]
    Last edited by a moderator: May 5, 2017
  4. Jan 22, 2012 #3


    Staff: Mentor

    You have
    [tex]du = \frac{e^{\sqrt{x}}}{2\sqrt{x}}dx = \frac{1}{2\sqrt{x}e^{-\sqrt{x}}}dx[/tex]

    The part you have circled (and including dx) is 2du.
    Last edited by a moderator: May 5, 2017
  5. Jan 24, 2012 #4
    Thanks, I get it now.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook