Results 1 to 2 of 2

Thread: what is the radius of convergence of the power series Σan xⁿ

  1. December 27th 2011, 06:18 AM #1
    sorv1986
    sorv1986 is offline
    Junior Member sorv1986's Avatar
    Joined
    May 2011
    From
    kolkata, india
    Posts
    33

    Cool what is the radius of convergence of the power series Σan xⁿ

    suppose Σan xⁿ be a power series and an= the number of divisors of n⁵⁰.

    Then what will be the radius of convergence of this power series?

    Thanks in advance . regards.
    Follow Math Help Forum on Facebook and Google+
  2. December 27th 2011, 07:15 AM #2
    FernandoRevilla
    FernandoRevilla is offline
    MHF Contributor FernandoRevilla's Avatar
    Joined
    Nov 2010
    From
    Madrid, Spain
    Posts
    2,154
    Thanks
    38

    Re: what is the radius of convergence of the power series Σan xⁿ

    Quote Originally Posted by sorv1986 View Post
    suppose Σan xⁿ be a power series and an= the number of divisors of n⁵⁰. Then what will be the radius of convergence of this power series?
    Hint 1\leq a_n\leq n^{50}\Rightarrow 1\leq a_n^{1/n}\leq (n^{1/n})^{50} . Now, apply the Sandwich Theorem.
    Follow Math Help Forum on Facebook and Google+
« Complex Variables and Binomial Theorem | asymptotic curve on a complete surface. »

Similar Math Help Forum Discussions

  1. what is the radius of convergence of that power series
    Posted in the Differential Geometry Forum
    Replies: 2
    Last Post: December 2nd 2011, 04:27 AM
  2. radius of convergence of the power series
    Posted in the Differential Geometry Forum
    Replies: 2
    Last Post: April 3rd 2011, 02:22 AM
  3. the radius of convergence of the power series
    Posted in the Calculus Forum
    Replies: 1
    Last Post: November 15th 2010, 02:34 PM
  4. Radius of Convergence of Power Series
    Posted in the Calculus Forum
    Replies: 5
    Last Post: January 27th 2010, 09:14 AM
  5. power series, radius of convergence.
    Posted in the Calculus Forum
    Replies: 2
    Last Post: January 26th 2008, 02:44 AM

Search Tags


/mathhelpforum @mathhelpforum