Results 1 to 2 of 2

Math Help - Integral Help

  1. #1
    VkL
    VkL is offline
    Member
    Joined
    Oct 2008
    Posts
    96

    Integral Help

    Integral of [ (2x+3) / (x^2 +2x + 5)^2 ] dx

    How do I begin? Partial fractions?
    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 VkL View Post
    Integral of [ (2x+3) / (x^2 +2x + 5)^2 ] dx

    How do I begin? Partial fractions?
    Nope, partial fractions won't work here. I'm running on too little sleep to figure out why. But trig. substitution will work!

    Note that your integral is: \displaystyle \int \frac {2x + 3}{[(x + 1)^2 + 4]^2}~dx

    So let \displaystyle x + 1 = 2 \tan \theta and your integral becomes:

    \displaystyle \int \frac {4 \tan \theta + 1}{8 \sec^2 \theta}~d \theta

    which is very doable. The rest is left to you. Don't forget to back-substitute when done
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: August 31st 2010, 08:38 AM
  2. Replies: 1
    Last Post: June 2nd 2010, 03:25 AM
  3. Replies: 0
    Last Post: May 9th 2010, 02:52 PM
  4. [SOLVED] Line integral, Cauchy's integral formula
    Posted in the Differential Geometry Forum
    Replies: 7
    Last Post: September 16th 2009, 12:50 PM
  5. Replies: 0
    Last Post: September 10th 2008, 08:53 PM

Search Tags


/mathhelpforum @mathhelpforum