An Inequality for Trigonometric Polynomials
N. K. Govil ; Mohammed A. Qazi ; Qazi I. Rahman
Bulletin of the Polish Academy of Sciences. Mathematics, Tome 60 (2012), p. 241-247 / Harvested from The Polish Digital Mathematics Library
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The main result says in particular that if t(ζ):=∑ν=-nⁿcνeiνζ is a trigonometric polynomial of degree n having all its zeros in the open upper half-plane such that |t(ξ)| ≥ μ on the real axis and cₙ ≠ 0, then |t’(ξ)| ≥ μn for all real ξ.

Publié le : 2012-01-01
EUDML-ID : urn:eudml:doc:281159 
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N. K. Govil; Mohammed A. Qazi; Qazi I. Rahman. An Inequality for Trigonometric Polynomials. Bulletin of the Polish Academy of Sciences. Mathematics, Tome 60 (2012) pp. 241-247. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-ba60-3-4/