Determine whether the series is convergent or divergent.

  1. Hello,

    I have to determine whether the series converges or diverges.

    It is [tex]\Sigma[/tex] (-1)^n * cos(Pi/n) where n=1 and goes to infinity.

    First I took the absolute value of the function and got the limit from n to infinity of cos(pi/n) and as a result I got 1 because cos(0)=1. However my text book says it's divergent. Could you please help me understand why it is divergent?

    Thank you!
  2. jcsd
  3. Nevermind! I figured out why. I guess I confused the alternating series test with some other one. :)

Know someone interested in this topic? Share this thead via email, Google+, Twitter, or Facebook

Have something to add?