Results 1 to 4 of 4

Thread: Geometric progression

  1. #1
    Newbie
    Joined
    Apr 2017
    From
    Israel
    Posts
    14

    Geometric progression

    P = a1 + a4 + a7 + a10..... + a34
    Q = a2 + a5 + a8 + a11 .... + a35

    how many terms in each one?

    The answer is 12


    * i came to conclusion that the q for each one is q3
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Apr 2005
    Posts
    19,167
    Thanks
    2814

    Re: Geometric progression

    It is certainly true that both 1, 4, 7, ..., 34, and 2, 5, 8, ..., 35 are arithmetic sequences with common difference 3 so, since 34= 1+ 3(11), and 35= 2+ 3(11), each has 11+ 1= 12 terms. I have no idea what "the q for each one is q^3" means.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Apr 2017
    From
    Israel
    Posts
    14

    Re: Geometric progression

    Quote Originally Posted by HallsofIvy View Post
    It is certainly true that both 1, 4, 7, ..., 34, and 2, 5, 8, ..., 35 are arithmetic sequences with common difference 3 so, since 34= 1+ 3(11), and 35= 2+ 3(11), each has 11+ 1= 12 terms. I have no idea what "the q for each one is q^3" means.
    What's the 11 for?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Aug 2006
    Posts
    21,194
    Thanks
    2624
    Awards
    1

    Re: Geometric progression

    Quote Originally Posted by Mustafashama View Post
    What's the 11 for?
    $P=\{a\times a^n:n=0,1,2,3,4,5,5,6,7,8,9,10,11\}$
    That is twelve values of $n$.
    Last edited by Plato; Jun 17th 2017 at 06:09 AM.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 9
    Last Post: Aug 9th 2012, 09:33 AM
  2. Geometric progression: An ant
    Posted in the Pre-Calculus Forum
    Replies: 3
    Last Post: May 9th 2011, 06:23 AM
  3. Geometric progression
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: Jan 16th 2010, 07:06 PM
  4. Geometric Progression or Geometric Series
    Posted in the Math Topics Forum
    Replies: 8
    Last Post: Oct 8th 2009, 07:31 AM
  5. Replies: 8
    Last Post: Mar 23rd 2009, 07:26 AM

/mathhelpforum @mathhelpforum