Results 1 to 2 of 2

Math Help - Question About Series

  1. #1
    Newbie
    Joined
    Jan 2009
    Posts
    14

    Question About Series

    I have 2 general questions:

    #1: How do I find the sum of a harmonic series? My book uses the example of the sum of 1/n from n=1 to infinity.

    #2: So far, for all of the problems I've worked in which I'm asked to find if a given series converges/diverges and to find it's sum, the series has either been geometric or telescoping (sometimes after a bit of rearranging).

    What's the general method for finding the sum if the series isn't geometric, telescoping, or harmonic? I think there is another kind called factorial, but I haven't learned that one yet.

    Also, I'm aware of what the definition states; but if I could see an example problem worked in which the series cannot be transformed into any of the above, that would be wonderful. Thanks!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Jul 2009
    Posts
    152
    1. To my knowledge, there is only one Harmonic Series, \sum_{n=1}^\infty \frac{1}{n}, and it diverges (slowly). Therefore it has no sum.
    2. There are many types or classes of infinite series: geometric series, telescoping series, power series, Taylor series, E-Series, series of functions, Laurent series, and on and on. There are some guidelines for summing each kind of series, (there are even strategies for "summing" certain divergent series), but there is nothing like a general formula that simply spits out a sum for whatever series you input. One learns different classes/types of series, and some general strategies for solving them. In some cases, quite a bit of ingenuity is required to demonstrate that a given series sums to a given value.

    If you have a specific series in mind that you need to sum, please provide it and one of us may be able to point you in the needed direction.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. question about answer to fourier series question
    Posted in the Advanced Math Topics Forum
    Replies: 11
    Last Post: February 9th 2011, 12:29 PM
  2. Replies: 0
    Last Post: January 26th 2010, 08:06 AM
  3. Series Question
    Posted in the Calculus Forum
    Replies: 3
    Last Post: September 29th 2009, 04:27 PM
  4. Sequences and Series - Power Series Question
    Posted in the Calculus Forum
    Replies: 3
    Last Post: April 20th 2008, 07:32 PM
  5. Replies: 6
    Last Post: August 18th 2007, 12:13 PM

Search Tags


/mathhelpforum @mathhelpforum