Results 1 to 3 of 3
Like Tree1Thanks
  • 1 Post By princeps

Math Help - generalised formula for the series

  1. #1
    Member
    Joined
    Nov 2010
    Posts
    95

    generalised formula for the series

    Hi, given the property for a series such that the second term is got by adding a constant 'd' to the 1st term and the 3rd term is got by multiplying the 2nd term by another constant 'r' and so on ..how can we arrive at a generalised formula for nth term of the series if we are given the 1st term , d and r?
    E.g if first term = 2, d = 2 ,r = 3 then the series is :
    2,4,12,14,42,44,132,134,...
    so the 4th term is 14, 7th term is 132 and so on..
    Thanks
    Last edited by pranay; March 12th 2012 at 03:14 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member
    Joined
    Nov 2011
    From
    Crna Gora
    Posts
    420
    Thanks
    64

    Re: generalised formula for the series

    Quote Originally Posted by pranay View Post
    Hi, given the property for a series such that the second term is got by adding a constant 'd' to the 1st term and the 3rd term is got by multiplying the 2nd term by another constant 'r' and so on ..how can we arrive at a generalised formula for nth term of the series if we are given the 1st term , d and r?
    E.g if first term = 2, d = 2 ,r = 3 then the series is :
    2,4,12,14,42,44,132,134,...
    so the 4th term is 14, 7th term is 132 and so on..
    Thanks
    A) If n is an even number :

     a_n=a_1 \cdot r^{\frac{n-2}{2}}+d \cdot \displaystyle \sum_{i=0}^{\frac{n-2}{2}} r^i

    B) If n is an odd number :

     a_n=a_1 \cdot r^{\frac{n-1}{2}}+d \cdot \displaystyle \sum_{i=1}^{\frac{n-1}{2}} r^i
    Thanks from pranay
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Nov 2010
    Posts
    95

    Re: generalised formula for the series

    Thanks a lot princeps
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] Interpreting generalised momenta
    Posted in the Advanced Applied Math Forum
    Replies: 2
    Last Post: January 15th 2012, 09:01 AM
  2. generalised pigeonhole principle
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: December 28th 2009, 04:13 AM
  3. generalised binominal theorem question
    Posted in the Calculus Forum
    Replies: 1
    Last Post: August 16th 2009, 09:19 PM
  4. How can we use generalised likelihood ratio test to d this?
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: March 1st 2009, 01:26 AM
  5. [SOLVED] Generalised Linear Models, Deviance
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: August 16th 2006, 02:18 PM

Search Tags


/mathhelpforum @mathhelpforum