Question 1023098
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Cannot determine the common ratio for:

Sequence: 4,-9, 16, -25,...

Series: 1 - 1/4 + 1/9 - 1/25 + ...

Must create a general term for both, and prove the convergence of the second using the alternating series test.
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1. I can not also.

  They are not Geometric progression. Neither first, nor the second.


2. The general term for the first sequence is {{{(-1)^(n+1)*(n+1)^2}}}, n = 1, 2, 3 . . . 


3. The alternating series test says: if {{{a[n]}}} decreases monotonically and  {{{lim}}} {{{a[n]}}} = {{{0}}} when n --> {{{infinity}}}, 
   then the alternating series converges.

   For your series the condition is valid, so the conclusion is valid too.
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