Results 1 to 2 of 2

Math Help - Basic Problem

  1. #1
    Pom
    Pom is offline
    Newbie
    Joined
    Oct 2007
    Posts
    3

    Exclamation Basic Problem

    the series 5, 9, 14, 20
    what is the equation for the nth term????
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor red_dog's Avatar
    Joined
    Jun 2007
    From
    Medgidia, Romania
    Posts
    1,252
    Thanks
    5
    a_1=5
    a_2=9=5+4=a_1+1+3
    a_3=14=9+5=a_2+2+3
    a_4=20=14+6=a_3+3+3
    .................................................
    So, a_n=a_{n-1}+(n-1)+3
    Adding the equalities we have
    a_n=5+[1+2+3+\ldots+(n-1)]+3(n-1)=5+\frac{n(n-1)}{2}+3(n-1)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Basic Problem of something more?
    Posted in the Algebra Forum
    Replies: 1
    Last Post: October 17th 2011, 01:18 PM
  2. Can't do this basic problem!
    Posted in the Algebra Forum
    Replies: 9
    Last Post: May 18th 2010, 03:55 AM
  3. basic problem
    Posted in the Algebra Forum
    Replies: 4
    Last Post: April 9th 2010, 09:40 PM
  4. Basic problem...??
    Posted in the Math Topics Forum
    Replies: 2
    Last Post: November 8th 2009, 09:55 AM
  5. Need help with a basic problem :)
    Posted in the Algebra Forum
    Replies: 3
    Last Post: July 2nd 2006, 12:33 PM

Search Tags


/mathhelpforum @mathhelpforum