Results 1 to 9 of 9

Math Help - converges to zero proof

  1. #1
    Member
    Joined
    Feb 2008
    Posts
    184

    converges to zero proof

    Prove xn = 2/n + 5/n^2 converges to zero.

    Is this a valid proof?

    We know 1/n
    converges to zero. Hence, by Lemma 10 so does 2/n What shall i say about 5/n^2 to complete the answer/proof?

    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,605
    Thanks
    1573
    Awards
    1
    Quote Originally Posted by charikaar View Post
    Prove xn = 2/n + 5/n^2 converges to zero.

    Is this a valid proof?

    We know 1/n
    converges to zero. Hence, by Lemma 10 so does 2/n What shall i say about 5/n^2 to complete the answer/proof?

    If n\ge 6 then 0<\frac{5}{n^2}<\frac{1}{n}.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Feb 2008
    Posts
    184
    Quote Originally Posted by Plato View Post
    If n\ge 6 then 0<\frac{5}{n^2}<\frac{1}{n}.


    (xn)n=1 to infinity is a sequence.I think the question should be: does this sequence xn = 2/n + 5/n^2 converge to zero? Prove your answer.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Apr 2005
    Posts
    15,303
    Thanks
    1277
    Which Plato has done nicely. What is your objection?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Member
    Joined
    Feb 2008
    Posts
    184
    Quote Originally Posted by HallsofIvy View Post
    Which Plato has done nicely. What is your objection?
    What about 0<n<6?
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,605
    Thanks
    1573
    Awards
    1
    Quote Originally Posted by charikaar View Post
    What about 0<n<6?
    I am sorry, but that laughable?
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Member
    Joined
    Feb 2008
    Posts
    184
    Quote Originally Posted by Plato View Post
    I am sorry, but that laughable?
    that emoticon is (skype thinking).

    to prove convergence, are we only interested in larger n i.e we ignore 0<n<6 as in this question.
    Follow Math Help Forum on Facebook and Google+

  8. #8
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,605
    Thanks
    1573
    Awards
    1
    Quote Originally Posted by charikaar View Post
    to prove convergence, are we only interested in larger n i.e we ignore 0<n<6 as in this question.
    It is impossible to help someone who has no clue about the basic concepts involved in the question at hand.
    Follow Math Help Forum on Facebook and Google+

  9. #9
    Member
    Joined
    Feb 2008
    Posts
    184
    Quote Originally Posted by Plato View Post
    It is impossible to help someone who has no clue about the basic concepts involved in the question at hand.
    I am trying to learn new stuff.

    Your help is much appreciated Plato
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. converges
    Posted in the Differential Geometry Forum
    Replies: 1
    Last Post: May 5th 2011, 03:33 AM
  2. Replies: 1
    Last Post: May 18th 2010, 10:31 PM
  3. converges to L
    Posted in the Differential Geometry Forum
    Replies: 2
    Last Post: March 8th 2010, 08:08 PM
  4. Converges
    Posted in the Differential Geometry Forum
    Replies: 1
    Last Post: September 18th 2009, 09:31 AM
  5. Replies: 2
    Last Post: November 8th 2008, 06:58 AM

Search Tags


/mathhelpforum @mathhelpforum