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Maclaurin series expansion

  1. Sep 20, 2008 #1
    Hi all,
    I am trying to work out a series expansion for ln ((x+1)/(x-1)).

    I have got the series expansion for ln(x+1) ie x- (x^2/2) + (x^3/3) - (x^4/4) ...

    and for ln(x-1) -x- (x^2/2) - (x^3/3) - (x^4/4) ...

    Can I tie these two together to get the series for ln ((x+1)/(x-1)).

    Or do I treat this as a new series.

  2. jcsd
  3. Sep 20, 2008 #2


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    Welcome to PF!

    Hi Brendan! Welcome to PF! :smile:

    Yes, you can just subtract them …

    but do you really mean ln(x-1) … at x = 0, that would be ln(-1) … do you mean ln(1-x)? :smile:
  4. Sep 21, 2008 #3
    Thanks alot I did mean ln(1-x).

    Heres the expansion

    2x + (2/3)x^3 + (2/5)x^5+ (2/7)x^7

    Once again thanks
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