Results 1 to 3 of 3

Math Help - Partial fractions - I have trouble solving this one

  1. #1
    Newbie
    Joined
    Apr 2012
    From
    UK
    Posts
    2

    Partial fractions - I have trouble solving this one

    Hi,

    I have managed to successfully answer all of the other partial fractions questions in my textbook but can't see how the following one is done:



    The denominator is factorised to:



    And then the textbook has been giving the following method to allow solving for A and B as the numerators:




    I am having trouble knowing what to make x to cancel out the A part and thus solve for B. To make A = 0 wouldn't x have to = 0.333...

    This is the answer given in the back of the book:




    Anyway, like I said, I have been OK with the other 10 or so examples but this one has thrown me off and I have spent a long time thinking about it hopefully I have just overlooked something simple.

    Any help is much appreciated.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member
    Joined
    Mar 2012
    From
    Sheffield England
    Posts
    440
    Thanks
    76

    Re: Partial fractions - I have trouble solving this one

    It is an identity so true for all values of x. Put x=1/3. This will find you B. Then put in any other x (say x=0) to get A.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Apr 2012
    From
    UK
    Posts
    2

    Re: Partial fractions - I have trouble solving this one

    Thanks for you quick reply, it was really bugging me.

    I have got it now, but I was genuinely stuck for long enough before that I signed up here, made those images in LaTeX etc.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] Solving Partial Fractions
    Posted in the Algebra Forum
    Replies: 2
    Last Post: August 23rd 2011, 07:34 PM
  2. solving partial fractions manually
    Posted in the Algebra Forum
    Replies: 3
    Last Post: February 13th 2011, 03:00 AM
  3. Solving an integral using partial fractions
    Posted in the Calculus Forum
    Replies: 2
    Last Post: July 1st 2010, 06:31 PM
  4. Replies: 0
    Last Post: April 28th 2010, 10:53 AM
  5. Replies: 4
    Last Post: September 11th 2009, 05:30 PM

Search Tags


/mathhelpforum @mathhelpforum