On the behaviour near the origin of sine series with convex coefficients
Publications de l'Institut Mathématique, _N_S_58 (1995) no. 72, p. 43
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Let a numerical sequence $\{a_k\}$ tend to zero and be convex.
We obtain estimates of
$
g(x) := \sum_{k=1}^{\infty} a_k \sin kx
$
for $x\,\to\,0$ expressed in terms of the
coefficients $a_k$. These estimates are of order- or asymptotic character.
For example, the following order equality is true:
$
g(x) \sim ma_m + \frac{1}{m} \sum_{k = 1}^{m - 1} k a_k,
$
where
$
x \in łeft ({\frac {\pi}{m+1}, \frac {\pi}{m}} \right ].
$
@article{PIM_1995_N_S_58_72_a5,
author = {S.A. Telyakovskii},
title = {On the behaviour near the origin of sine series with convex coefficients},
journal = {Publications de l'Institut Math\'ematique},
pages = {43 },
year = {1995},
volume = {_N_S_58},
number = {72},
zbl = {0945.42004},
language = {en},
url = {http://geodesic.mathdoc.fr/item/PIM_1995_N_S_58_72_a5/}
}
S.A. Telyakovskii. On the behaviour near the origin of sine series with convex coefficients. Publications de l'Institut Mathématique, _N_S_58 (1995) no. 72, p. 43 . http://geodesic.mathdoc.fr/item/PIM_1995_N_S_58_72_a5/