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Classes of Nonnegative Sine Polynomials

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Trigonometric Sums and Their Applications

Abstract

We present several one-parameter classes of nonnegative sine polynomials. One of our theorems states that the inequality

$$\displaystyle 0\leq \sum _{k=1}^n \Bigl (\frac {1}{n}+\frac {1}{k}\Bigr )(n-k+\alpha )\sin {}(kx) \quad {(\alpha \in \mathbb {R})} $$

holds for all n ≥ 1 and x ∈ [0, π] if and only if α ∈ [0, 3]. This extends a result of Dimitrov and Merlo (2002), who proved the inequality for α = 1.

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Correspondence to Horst Alzer .

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Alzer, H., Kwong, M.K. (2020). Classes of Nonnegative Sine Polynomials. In: Raigorodskii, A., Rassias, M. (eds) Trigonometric Sums and Their Applications. Springer, Cham. https://doi.org/10.1007/978-3-030-37904-9_3

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