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Is it an Alternating Series?

  • Thread starter remaan
  • Start date
  • #1
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Homework Statement



Is this an alternating series : (-1)^n / ( arctan n ) ^ (n)

Homework Equations



I know that the alternating series should have (-1) to any power, but also the signs should be - , + , - , + ..... or the opposit,

The Attempt at a Solution



I am ok with this I know that for testing Con. Or Div. of this we should use the root test

But this series. But the problem is " Is this seris alternating or not"

Becasue if not it will be treated normally with a root test and it will Con.

For me I think that it is not "Alternating "

What do you think ?
 

Answers and Replies

  • #2
Dick
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Does 1/arctan(n)^n decrease to zero? That's what they want to you check.
 
  • #3
132
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mmm, do you mean the limit, if so no. It goes to inifity.
 
  • #4
132
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So, this is NOT an alternating sries, right ????
 
  • #5
Dick
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No. 1/arctan(n)^n doesn't go to infinity. Tell me why you think it does.
 
  • #6
132
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ohhh, Ya , I remembred it goes to Pie/ 2
Right ?
 
  • #7
Dick
Science Advisor
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arctan(n) goes to pi/2. 1/arctan(n)^n doesn't.
 

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