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Determine whether the series is convergent or divergent.

  • Thread starter Sabricd
  • Start date
  • #1
27
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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!
 

Answers and Replies

  • #2
27
0
Nevermind! I figured out why. I guess I confused the alternating series test with some other one. :)

Thanks!
 

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