Does the Alternating Series Test Prove Convergence for Ʃ((-1)^n)*(n+1)/5^n?

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SUMMARY

The series Ʃ from n=1 to ∞ of ((-1)^n)*(n+1)/5^n converges by the Alternating Series Test. The test requires that the absolute value of the terms decreases monotonically and approaches zero. The discussion highlights the challenge of demonstrating that the sequence is decreasing, suggesting the use of the inequality a_{n+1} ≤ a_n to establish this property. The derivative method was deemed ineffective, indicating a need for alternative approaches to prove convergence.

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Homework Statement


Show that the series Ʃ 1 to ∞ ((-1)^n)*(n+1)/5^n converges using the alternating series test.


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The Attempt at a Solution


I don't know how to show the series is decreasing. I took the derivative of the function, but it got messy and I don't feel that was the correct way to go. Any help appreciated, thanks.
 
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