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!

Integration, u substitution with limits

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

    find ∫x/√(x+1).dx with limits 1 & 0

    using substitution x = u^2 -1


    2. Relevant equations



    3. The attempt at a solution

    dx = du

    x = u^2 -1

    u = √( x+1)

    sub limits of 1 & 0 into u.
    Hence new limits of √2 & 1

    Therefore,

    ∫ u^2 -1/ u

    = ∫ u - 1/u
    = 1/2 (u)^2 - ln u

    Plugging in limits of √2& 1

    (1/2 * 2 - ln √ 2 ) - (1/2)

    = ( 1/2 - 1/2 ln (2))

    Cant work out where I have stumbled, any ideas???
     
  2. jcsd
  3. Feb 22, 2012 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    hi sg001! :smile:
    noooo :redface:
     
  4. Feb 22, 2012 #3
    ohh that makes sense now because i had the same question but with different sub involved. ie u= x + 1,,, so I kinda got ahead of myself and skipped that step.
    Thanks for pointing that out, I probabaly would never have realised.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Integration, u substitution with limits
Loading...