Results 1 to 4 of 4

Math Help - Soln check:Int evaluation w/ sub rule

  1. #1
    Junior Member
    Joined
    Nov 2010
    Posts
    57

    Soln check:Int evaluation w/ sub rule

    \int_1^2 x\sqrt{x-1}dx

    I used the substituttion u^2 = x-1 \Rightarrow 2udu = dx \Rightarrow x = u^2 + 1 \Rightarrow u(2) = 1; u(1) = 0

    and the integral then becomes \int_0^1u(u^2+1)2udu \Rightarrow 2\int_0^1u^4 +u^2 correct??
    Last edited by Foxlion; April 26th 2012 at 05:02 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Junior Member
    Joined
    Nov 2010
    Posts
    57

    Re: Soln check:Int evaluation w/ sub rule

    I'm sorry for the random updates pressed 'enter ' TOO EARLY by mistake
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,861
    Thanks
    742

    Re: Soln check:Int evaluation w/ sub rule

    Hello, Foxlion!

    Lookin' good!

    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    12,045
    Thanks
    886

    Re: Soln check:Int evaluation w/ sub rule

    or ...

    \int_1^2 x\sqrt{x-1} \, dx

    u = x-1

    x = u+1

    du = dx

    \int_0^1 (u+1)\sqrt{u} \, du

    \int_0^1 u^{3/2} + u^{1/2} \, du
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Evaluation of Cos(2/3+i2)
    Posted in the Trigonometry Forum
    Replies: 3
    Last Post: August 12th 2011, 01:48 AM
  2. Evaluation of Sec...
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: October 28th 2010, 05:45 AM
  3. Replies: 1
    Last Post: September 25th 2009, 12:35 PM
  4. evaluation
    Posted in the Algebra Forum
    Replies: 8
    Last Post: August 7th 2009, 01:20 PM
  5. Evaluation
    Posted in the Math Topics Forum
    Replies: 4
    Last Post: January 28th 2007, 02:25 AM

Search Tags


/mathhelpforum @mathhelpforum