Bounds for the derivative of a certain class of rational functions


In this paper, we shall obtain the bounds for the derivative of a rational function in the supremum norm on the unit circle in both the directions by involving the moduli of all its zeros. The obtained results strengthen some recently proved results.

DOI Code: 10.1285/i15900932v41n2p9

Keywords: Rational functions; Polynomial inequalities; Zeros; Poles; Blaschke product

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