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

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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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Thread 'Prove that the integral is equal to ##\pi^2/8##'

Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
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