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Possible Duplicate:
Proving that the sequence $F_{n}(x)=\sum\limits_{k=1}^{n} \frac{\sin{kx}}{k}$ is boundedly convergent on $\mathbb{R}$

From Stewart, we cannot find a calculus 2 easy way to prove this:

$$\sum^{\infty}_{n=1}\frac{\sin[n]}{n}=\frac{1}{2}(\pi-1)$$

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  • $\begingroup$ What's $[n]$ suppose to be? perhaps the question has a typo? $\endgroup$ – Jean-Sébastien Nov 2 '12 at 19:05
  • $\begingroup$ Kerry just means $\sin(n)$ $\endgroup$ – user17762 Nov 2 '12 at 19:12
  • $\begingroup$ @BabakSorouh: But floor of a natural would be quite redundant. $\endgroup$ – Hagen von Eitzen Nov 2 '12 at 19:12
  • $\begingroup$ Yeah floor or $n$ is just $n$, but this may just be it because sum of $\sin(n)/n$ is $1/2(\pi-1)$ $\endgroup$ – Jean-Sébastien Nov 2 '12 at 19:16
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    $\begingroup$ Also look here math.stackexchange.com/questions/161960/… $\endgroup$ – user17762 Nov 2 '12 at 19:25
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$\sum\limits^{\infty}_{n=1}\dfrac{\sin{n\theta}}{n}$ is the Fourier series for $f(\theta)=\dfrac{\pi-\theta}{2}, \;\; 0<\theta<2\pi,$ and converges uniformly on every closed interval $[\alpha, \beta], \;\; 0<\alpha<\beta<2\pi$ by Dirichlet's test.

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