Results 1 to 2 of 2

Math Help - What's the formula for finding the terms in an arithmetic series?

  1. #1
    Newbie
    Joined
    Nov 2011
    Posts
    3

    What's the formula for finding the terms in an arithmetic series?

    Here's the math problem....

    In an arithmetic series, the terms of the series are equally spread out. For example, in 1+5+9+13+17, consecutive terms are 4 apart. If the first term in an arithmetic series is 3, the last term is 136, and the sum is 1,390, what are the first 3 terms?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5

    Re: What's the formula for finding the terms in an arithmetic series?

    Quote Originally Posted by krstybrght View Post
    Here's the math problem....

    In an arithmetic series, the terms of the series are equally spread out. For example, in 1+5+9+13+17, consecutive terms are 4 apart. If the first term in an arithmetic series is 3, the last term is 136, and the sum is 1,390, what are the first 3 terms?
    t_n = 136 = 3 + (n-1)d .... (1)

    S_n = 1390 = substitute formula for sum of n terms of an arithmetic series (look it up in your textbook or class notes) .... (2)

    Solve equations (1) and (2) simultaneously for d.

    Then t_r = 3 + (r-1)d and you substitute the value of d and the required values of r to get the terms.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: December 7th 2009, 03:49 AM
  2. Find, in terms of k... [Arithmetic series]
    Posted in the Algebra Forum
    Replies: 3
    Last Post: May 6th 2009, 02:45 AM
  3. Replies: 3
    Last Post: March 30th 2009, 04:54 AM
  4. Finding the next terms in series
    Posted in the Calculus Forum
    Replies: 2
    Last Post: April 22nd 2007, 09:45 AM
  5. Arithmetic series formula
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: November 26th 2005, 07:55 AM

Search Tags


/mathhelpforum @mathhelpforum