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Integral analogue of Turán-type inequalities concerning the polar derivative of a polynomial
Mayanglambam Singhajit Singh, Barchand Chanam National Institute of Technology Manipur
Abstract:
If $w(\zeta)$ is a polynomial of degree $n$ with all its zeros in $|\zeta|\leq \Delta,$ $\Delta\geq 1$ and any real $\gamma\geq 1$, Aziz
proved the integral inequality [1]
\begin{equation*}
\left\lbrace\int_{0}^{2\pi}\left|1+\Delta^ne^{i\theta}\right|^{\gamma}d\theta\right\rbrace^{{1}/{\gamma}}\max_{|\zeta|=1}|w^{\prime}(\zeta)|\geq n\left\lbrace\int_{0}^{2\pi}\left|w\left(e^{i\theta}\right)\right|^{\gamma}d\theta\right\rbrace^{{1}/{\gamma}}.
\end{equation*}
In this article, we establish a refined extension of the above integral inequality by using the polar derivative instead of the ordinary derivative consisting of the leading coefficient and the constant term of the polynomial. Besides, our result also yields other intriguing inequalities as special cases.
Keywords:
Polar derivative, Turán-type inequalities, Integral inequalities
Citation:
Mayanglambam Singhajit Singh, Barchand Chanam, “Integral analogue of Turán-type inequalities concerning the polar derivative of a polynomial”, Ural Math. J., 10:2 (2024), 131–143
Linking options:
https://www.mathnet.ru/eng/umj240 https://www.mathnet.ru/eng/umj/v10/i2/p131
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