Results 1 to 9 of 9

Math Help - Please check summation of infinite series?

  1. #1
    Newbie
    Joined
    Mar 2009
    Posts
    10

    Please check summation of infinite series?

    I need to take the sum of (1/k) - (1/(k+4)) as k--> 1 to infinity

    My answer is..

    -4/(k(k+4))

    Is that correct? Please help!!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor matheagle's Avatar
    Joined
    Feb 2009
    Posts
    2,763
    Thanks
    5
    Nope.
    The k is a dummy variable, the final answer is a number, possibly infinity, free of k.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Mar 2009
    Posts
    10
    Okay, so I just did some algebraic manipulation before but, that doesn't get to me the answer...then how do it go about it?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by pinkprincess08 View Post
    Okay, so I just did some algebraic manipulation before but, that doesn't get to me the answer...then how do it go about it?
    Write out the terms from k =1 to k = 9, say. What do you notice? What do you think is going to happen in the limt of k --> oo.

    Add up the terms that are not going to cancel in the limit.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor Calculus26's Avatar
    Joined
    Mar 2009
    From
    Florida
    Posts
    1,271
    See attachment only if you haven't figured it out based on Mr fantastic's sage advice.
    Attached Files Attached Files
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Newbie
    Joined
    Mar 2009
    Posts
    10
    Sk = 1+(1/2)+(1/3)+(1/4) ?
    Follow Math Help Forum on Facebook and Google+

  7. #7
    MHF Contributor matheagle's Avatar
    Joined
    Feb 2009
    Posts
    2,763
    Thanks
    5
    Quote Originally Posted by Calculus26 View Post
    See attachment only if you haven't figured it out based on Mr fantastic's sage advice.
    TYPO...
    you must have meant aged not saged advice.
    Follow Math Help Forum on Facebook and Google+

  8. #8
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by matheagle View Post
    TYPO...
    you must have meant aged not saged advice.
    Hardy ha ha. You're a fine one to talk, dad. I have googled you, you know. Only moo is allowed to make jokes about my age (because she's the only member [that I'm aware of] who knows what it is within a bull's roar - well, within a sd, anyway).

    Anyhow, since things are getting off-topic and the OP has solved the problem, I'll try and make my old athritic fingers type out Thread Clos



    Follow Math Help Forum on Facebook and Google+

  9. #9
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by pinkprincess08 View Post
    Sk = 1+(1/2)+(1/3)+(1/4) ?
    Looks OK (to my aged eyes)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: December 21st 2011, 09:55 AM
  2. Help with infinite Summation
    Posted in the Advanced Math Topics Forum
    Replies: 1
    Last Post: November 7th 2010, 08:18 PM
  3. finding value of summation of infinite series
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: May 4th 2010, 05:23 AM
  4. infinite summation problem
    Posted in the Pre-Calculus Forum
    Replies: 3
    Last Post: March 14th 2010, 06:55 PM
  5. Infinite summation
    Posted in the Statistics Forum
    Replies: 0
    Last Post: January 18th 2010, 01:55 PM

Search Tags


/mathhelpforum @mathhelpforum