SOLUTION: 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

Algebra ->  Sequences-and-series -> SOLUTION: 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      Log On


   



Question 1023098: 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.

Answer by ikleyn(52787) About Me  (Show Source):
You can put this solution on YOUR website!
.
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 %28-1%29%5E%28n%2B1%29%2A%28n%2B1%29%5E2, n = 1, 2, 3 . . . 


3. The alternating series test says: if a%5Bn%5D decreases monotonically and  lim a%5Bn%5D = 0 when n --> infinity, 
   then the alternating series converges.

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