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: Partial fractions

  1. Sep 19, 2012 #1
    1. The problem statement, all variables and given/known data
    determine the indefinite integral: ∫ (4x+10)/(9x^2+24x+16) dx


    2. Relevant equations
    partial fractions technique


    3. The attempt at a solution

    i know it's partial fractions and i thought i did it right but i got the wrong answer.

    (4x+10)/(9x^2+24x+16) = (4x+10)/(3x+4)^2 = A/(3x+4) + B/(3x+4)^2
    is that part right before I continue?
     
  2. jcsd
  3. Sep 19, 2012 #2

    Ray Vickson

    User Avatar
    Science Advisor
    Homework Helper

    Yes, that is the right idea.

    RGV
     
  4. Sep 19, 2012 #3
    Yes, that's right.
     
  5. Sep 19, 2012 #4

    HallsofIvy

    User Avatar
    Science Advisor

    As others have told you that is correct. Now multiply both sides by (3x+4)^2 to get (4x+10)(3x+ 4)^2= A(3x+ 4)+ B. Taking x= -4/3 gives an easy solution for B. Take x to be any other number, say, x= 0, to get an equation for A.
     
  6. Sep 19, 2012 #5
    ohhhh .. i see what i did. ok .. so i was doing A(3x+ 4)^2 + B(3x+4) not realizing the denominator difference. stupid mistake. thanks!
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook