Results 1 to 6 of 6

Math Help - Series & Sequences

  1. #1
    Member >_<SHY_GUY>_<'s Avatar
    Joined
    Jan 2008
    From
    CA
    Posts
    181

    Unhappy Series & Sequences

    how do you find the sum of an infinite series?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member vincisonfire's Avatar
    Joined
    Oct 2008
    From
    Sainte-Flavie
    Posts
    469
    Thanks
    2
    Awards
    1
    Depending on the series, there are tricks sometimes ... often not. A well-known case are the geometric series where you can multiply by a factor of (x-1) and everything cancel in a nice way. It only converges for  1 \geq r \geq -1 though.
     \sum_{i=0}^n x^i = \frac{1-x^{n+1}}{1-x}
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Jan 2009
    Posts
    9
    \frac{a}{1-r}

    Where a = first term in the sequence
    r = common ratio (-1<x<1)
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by Lupin View Post
    \frac{a}{1-r}

    Where a = first term in the sequence
    r = common ratio (-1<x<1)
    It should be said that this the sum of an infinite geometric series.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by >_<SHY_GUY>_< View Post
    how do you find the sum of an infinite series?
    Your question is too broad. Please be specific. What sort of infinite series? Give an example.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor Mathstud28's Avatar
    Joined
    Mar 2008
    From
    Pennsylvania
    Posts
    3,641
    Quote Originally Posted by >_<SHY_GUY>_< View Post
    how do you find the sum of an infinite series?
    Mr. F is right, this question is WAY to broad to answer...this goes right up there with "How do you integrate?" and "How does one drive a vehicle?"...but Im sure youll come back and give us an example

    I do think I ought to mention some of the most common ways. They include (but of course are not limited to): power series, fourier Series, riemann sums, telescoping sums, and function definitions.

    This of course is itself a very broad and unfufilling answer, but this is intentional. Research these methods and if you have any questions pertaining to them or others just ask. Im sure either myself or one of the other members here will be glad to oblige your hungry mind


    EDIT: Jeez...I sound kinda loopy and eccentric dont I
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Sequences, Series, etc.
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: February 16th 2010, 08:18 PM
  2. Series and Sequences
    Posted in the Calculus Forum
    Replies: 2
    Last Post: December 9th 2009, 05:42 AM
  3. Sequences/Series
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: October 18th 2009, 11:08 PM
  4. Sequences and Series
    Posted in the Algebra Forum
    Replies: 4
    Last Post: September 4th 2009, 12:05 PM
  5. Sequences and Series - Power Series Question
    Posted in the Calculus Forum
    Replies: 3
    Last Post: April 20th 2008, 07:32 PM

Search Tags


/mathhelpforum @mathhelpforum