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: Help with this integral

  1. Jul 3, 2013 #1
    I tried Partial fractions,, I completed the square which is (x-1)^2-3 ,, but,, what to do with the numer 3??? i tried trig sub also,, didnt worked,,
    Any ideas on how to integrate?
    Is there a way to simplify??

    Thanks a lot,,

    Attached Files:

  2. jcsd
  3. Jul 3, 2013 #2


    User Avatar
    Homework Helper

    Express the numerator as (2x-2) + 3.

    Split up the expression. The first integrand is of the form f'(x)/f(x).

    For the second integral, it's probably easiest to just factorise the expression, then use partial fractions. You may have some surds to deal with, but it's still quite simple.

    Sorry for the multiple edits, I'm rushing for time and am doing this in my head.
  4. Jul 3, 2013 #3

    ,, but why did you express it like that? (2x-2) + 3 thanks a lot, is see I can use use u sub since d/dx of x^2-2x-2 = 2x-2.. but i woul like to know how and why did you expressit like that,... thank you!
  5. Jul 3, 2013 #4


    User Avatar
    Homework Helper

    I hope you took notice of my edited post.

    Why did I express it like that? It's just pattern recognition. I guess I just taught myself to recognise that form f'(x)/f(x) "hiding" in an integrand.
  6. Jul 3, 2013 #5
    ? but the 3 , where did you get it from? Would you mind to explain me really quick? Thanks
  7. Jul 3, 2013 #6


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    (2x-2)+3 = ?
  8. Jul 3, 2013 #7
    The procedure,, i would really appreciate
  9. Jul 3, 2013 #8


    User Avatar
    Homework Helper

    I figured out what f'(x) would be, then what I had to add on to it to make the numerator in the integrand.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted