Saturday, 12 December 2015

sequences and series - Convergence of sumik=1nftyfracsin(k(k1))k

In connection with the strange behavious of a certain sum in Mathematica (https://mathematica.stackexchange.com/q/210849/16361) I suspected a possible divergence but I could not prove of disprove it.



Here's the question: is the sum




s1=k=1sin(k(k1))k



convergent or divergent?



Similarly with



s2=k=1sin(k2)k



Numerical evidence (partial sums) seem to indicate convergence.




EDIT 07.12.19



Actually, the story began one step earlier: I considered this unanswered question Convergence of n=1sin(n!)n



s3=k=1sin(k!)k



and wanted to simplify it replacing k! with something simpler.

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