Some Inequalities for the Polar Derivative of a Polynomial
Kragujevac Journal of Mathematics, Tome 47 (2023) no. 4, p. 567
Cet article a éte moissonné depuis la source eLibrary of Mathematical Institute of the Serbian Academy of Sciences and Arts
Let $P(z)$ be a polynomial of degree $n$ which has no zeros in $|z|1$, then it was proved by Liman, Mohapatra and Shah \cite{moh} that \begin{align*} |zD_lpha P(z) + n\beta eft( \frac{|lpha|-1}{2}\right) P(z)\right| eq {}\frac{n}{2}eftbrace eft|lpha +\beta eft( \frac{|lpha|-1}{2}\right) \right|+eft|z+\betaeft(\frac{|lpha|-1}{2}\right)\right|\right\rbrace \maximits_{|z|=1}|P(z)| -\frac{n}{2}eftbrace eft|lpha + \betaeft(\frac{|lpha|-1}{2} \right) \right|-eft|z +\betaeft( \frac{|lpha|-1}{2}\right) \right|\right\rbrace \minimits_{|z|=1}|P(z)|, \end{align*} for any $\beta$ with $|\beta|\leq 1$ and $|z|=1$. In this paper we generalize the above inequality and our result also generalizes certain well known polynomial inequalities.
Classification :
30A10, 30C15, 30D15
Keywords: polynomial, Bernstein inequality, polar derivative
Keywords: polynomial, Bernstein inequality, polar derivative
@article{KJM_2023_47_4_a6,
author = {M. H. Gulzar and B. A. Zargar and Rubia Akhter},
title = {Some {Inequalities} for the {Polar} {Derivative} of a {Polynomial}},
journal = {Kragujevac Journal of Mathematics},
pages = {567 },
year = {2023},
volume = {47},
number = {4},
language = {en},
url = {http://geodesic.mathdoc.fr/item/KJM_2023_47_4_a6/}
}
M. H. Gulzar; B. A. Zargar; Rubia Akhter. Some Inequalities for the Polar Derivative of a Polynomial. Kragujevac Journal of Mathematics, Tome 47 (2023) no. 4, p. 567 . http://geodesic.mathdoc.fr/item/KJM_2023_47_4_a6/