5
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SumConvergence[(-1)^(n + 1) ((Cos[n^2] + Sin[n + 2])/7^n), n]

Mathematica fails to provide a result (true/false) but wolfram alpha works. What should I do ?

It gives $$\text{SumConvergence}\left[(-1)^{n+1} 7^{-n} \left(\cos \left(n^2\right)+\sin (n+2)\right),n\right]$$

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  • $\begingroup$ Mathematica 9.0.1 gives True though. Can you mention your precise Mathematica version? I assume 10.0.2. $\endgroup$ – Szabolcs Jan 23 '15 at 16:56
  • $\begingroup$ yes 10.0.0.0 version $\endgroup$ – GorillaApe Jan 23 '15 at 16:59
  • 2
    $\begingroup$ Please mention that in the question. Unrelated: you really should upgrade to 10.0.2. It won't fix this problem but it will fix many others. $\endgroup$ – Szabolcs Jan 23 '15 at 17:00
  • $\begingroup$ Version 8 doesn't give a result, so it looks 9 is unique in this. $\endgroup$ – Sjoerd C. de Vries Jan 23 '15 at 22:41
  • $\begingroup$ Fixed in V11.2.0 $\endgroup$ – Michael E2 Jan 9 '18 at 22:24

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