On the Location of the Zeros of Certain Polynomials
Publications de l'Institut Mathématique, _N_S_99 (2016) no. 113, p. 287
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We extend Aziz and Mohammad's result that the zeros, of a polynomial $P(z)=\sum_{j=0}^na_jz^j$, $ta_j\geq a_{j-1}>0$, $j=2,3,\dots,n$ for certain $t$ (${}>0$), with moduli greater than $t(n-1)/n$ are simple, to polynomials with complex coefficients. Then we improve their result that the polynomial $P(z)$, of degree $n$, with complex coefficients, does not vanish in the disc \[ |z-a e^{ilpha}|/(2n);a>0,\max_{|z|=a}|P(z)|=|P(ae^{ilpha})|, \] for $r$ being the greatest positive root of the equation \[ x^n-2x^{n-1}+1=0, \] and finally obtained an upper bound, for moduli of all zeros of a polynomial, (better, in many cases, than those obtainable from many other known results).
Classification :
30C15 30C10
Keywords: simple zeros, zero free region, refinement, upper bound for moduli of all zeros
Keywords: simple zeros, zero free region, refinement, upper bound for moduli of all zeros
@article{10_2298_PIM1613287B,
author = {S. D. Bairagi and Vinay Kumar Jain and T. K. Mishra and L. Saha},
title = {On the {Location} of the {Zeros} of {Certain} {Polynomials}},
journal = {Publications de l'Institut Math\'ematique},
pages = {287 },
publisher = {mathdoc},
volume = {_N_S_99},
number = {113},
year = {2016},
doi = {10.2298/PIM1613287B},
language = {en},
url = {http://geodesic.mathdoc.fr/articles/10.2298/PIM1613287B/}
}
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S. D. Bairagi; Vinay Kumar Jain; T. K. Mishra; L. Saha. On the Location of the Zeros of Certain Polynomials. Publications de l'Institut Mathématique, _N_S_99 (2016) no. 113, p. 287 . doi: 10.2298/PIM1613287B
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