Results 1 to 2 of 2

Math Help - ap's...kinda stuck

  1. #1
    Newbie
    Joined
    Jan 2010
    Posts
    12

    ap's...kinda stuck

    Hi all
    the question is about arithmetic series and i get them but i haven't come across a question like this before and i don't get what to do...
    it says the first term of an arithmetic series is 3 and the seventh term is twice the third term.
    (i) find the common difference ( i know for the common difference you need to have a constant addition or subtraction rule but i don't get how to work it out :S)
    (ii) calculate the sm of the first 20 terms of the series (i know the equation but i don't know how to use it :S )

    thank you sooo much and sorry if you've seen questions like these a million times xx
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Grandad's Avatar
    Joined
    Dec 2008
    From
    South Coast of England
    Posts
    2,570
    Thanks
    1
    Hello katiethegreat
    Quote Originally Posted by katiethegreat View Post
    Hi all
    the question is about arithmetic series and i get them but i haven't come across a question like this before and i don't get what to do...
    it says the first term of an arithmetic series is 3 and the seventh term is twice the third term.
    (i) find the common difference ( i know for the common difference you need to have a constant addition or subtraction rule but i don't get how to work it out :S)
    (ii) calculate the sm of the first 20 terms of the series (i know the equation but i don't know how to use it :S )

    thank you sooo much and sorry if you've seen questions like these a million times xx
    I answered a question very similar to this just here.

    Read it through carefully and have another go at your problem. If you're still stuck get back to us.

    Grandad
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 5
    Last Post: March 4th 2010, 07:37 PM
  2. calculus help~ kinda engineering
    Posted in the Calculus Forum
    Replies: 1
    Last Post: December 10th 2008, 11:14 PM
  3. Replies: 3
    Last Post: December 17th 2007, 02:27 AM
  4. Kinda stuck with this one
    Posted in the Advanced Applied Math Forum
    Replies: 8
    Last Post: August 27th 2007, 05:00 PM
  5. oh boy... kinda lost, square
    Posted in the Geometry Forum
    Replies: 3
    Last Post: December 4th 2006, 05:47 PM

Search Tags


/mathhelpforum @mathhelpforum