Korean J. Math. Vol. 29 No. 3 (2021) pp.631-638
DOI: https://doi.org/10.11568/kjm.2021.29.3.631

Inequalities concerning polynomial and its derivative

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Bashir Ahmad Zargar
Manzoor Hussain Gulzar
Tawheeda Akhter

Abstract

In this paper, some sharp inequalities for ordinary derivative P(z) and polar derivative DαP(z)=nP(z)+(αz)P(z) are obtained by including some of the coefficients and modulus of each individual zero of a polynomial P(z) of degree n not vanishing in the region |z|>k, k1. Our results also improve the bounds of Tur\'an's and Aziz's inequalities.



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References

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