1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Find radius of convergence and interval of convergence for the series

  1. Jul 18, 2013 #1

    emk

    User Avatar

    x^n/(2n-1) is the series. It starts at 1 and goes to infinity.

    I did the ratio test on it and got abs.(x)

    So the radius of convergence=1, and then I plugged -1 and 1 into the original series and got that they both converged. But the answer is [-1,1). Why aren't they both hard brackets?
     
  2. jcsd
  3. Jul 18, 2013 #2

    Zondrina

    User Avatar
    Homework Helper

    Pay special attention to x=1. When you plug it into your series you get ##\sum \frac{1}{2n-1}##.

    You know that diverges...

    Hint : Compare it to something you know diverges already.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted