On the Zeros of Polynomial With Real Coefficients


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Authors: M. I. MIR, J. BANOO, S. SARFARAJ AND J. G. DAR

DOI: 10.46793/KgJMat2606.1001M

Abstract:

The Eneström-Kakeya theorem provides essential bounds on the location of the zeros of a polynomial with positive coefficients. Lot of research work has been done regarding the classical theorem known as Eneström-Kakeya theorem concerning the regions containing zeros of a polynomial. This theorem states that if F(z) = λ=0nfλzλ is a polynomial with degree n with real coefficients satisfying 0 f0 f1 f2 ⋅⋅⋅fn, then all the zeros of F(z) lie in |z|≤ 1. In this article, we prove several extensions of this theorem which impose restrictions only on the coefficients f0,f1,,fn1 and leaves the coefficient fn to vary freely over the whole complex plane.



Keywords:

Complex polynomials, location of zeros, Eneström–Kakeya theorem, m onotonicity.



References:

[1]   N. Anderson, E. B. Saff and R. S. Varga, On the Eneström-Kakeya theorem and its sharpness, Linear Algebra Appl. 28 (1979), 5–16.

[2]   N. Anderson, E. B. Saff and R.S. Varga, An extension of the Eneström-Kakeya theorem and its sharpness, SIAM J. Math. Anal. 12 (1981), 10–22.

[3]   A. Aziz and B. A. Zargar, Some extensions of Eneström-Kakeya theorem, Glasnick Matematicki 31 (1996), 239–244.

[4]   A. Aziz and B. A. Zargar, Bounds for the zeros of a polynomial with restricted coefficients, Appl. Math. 3 (2012), 30–33.

[5]   D. Tripathi, A note on Eneström-Kakeya theorem for a polynomial with quaternionic variable, Arab. J. Math. (2020).

[6]   G. Eneström, Härledning af en allmän formel för antalet pensionärer, som vid en godtyeklig tidpunkt förefinnas inom en sluten pensionslcassa, Övfers. Vetensk.-Akad. Fórhh. 50 (1893), 405–415.

[7]   R. B. Gardner, N. K. Govil and A. Weems, On the Eneström-Kakeya theorem and some of its generalizations, Current Topics in Pure and Computational Complex Analysis, Springer, 2014, 171–200.

[8]   N. K. Govil, On a theorem of Bernstein, Proceedings of the National Academy of Sciences, India Section A 50 (1980), 50–52.

[9]   N. K. Govil and Q. I. Rehman, On the Eneström-Kakeya theorem, Tohoku Math. J. 20(2) (1968), 126–136.

[10]   A. M. Hussain, A note on Eneström-Kakeya theorem for quaternionic polynomials, Korean J. Math. 30(3) (2022), 503–512.

[11]   A. Joyal, G. Labelle and Q. I. Rahman, On the location of zeros of polynomials, Canad. Math. Bull. 10 (1967), 53–63.

[12]   S. Kakeya, On the limits of the roots of an algebraic equation with positive coefficients, Tohoku Math. J. (1) 2 (1912), 140–142.

[13]   M. Kovačević and I. Milovanović, On the Eneström-Kakeya theorem, Tohoku Math. J. (1) 2 (1912), 140–142.

[14]   E. R. Nwaeze, Geometry of zeros and Bernstein type inequalities concerning growth for polynomials, PhD dissertation, Graduate Faculty of Auburn University, Auburn, Alabama, 2015.

[15]   N. A. Rather, I. Dar and A. Iqbal, Generalization of Eneström-Kakeya theorem and its extensions to analytic functions, J. Class. Anal. 16 (2020), 37–44.

[16]   N. A. Rather, M. Shafi and I. Dar, On the Eneström-Kakeya theorem, Appl. Math. E-Notes 22 (2022), 660–667.

[17]   N. A. Rather, I. Dar and A. Iqbal, On the regions containing all the zeros of polynomials and related analytic functions, Vestn. St. Peterbg. Uni. Math. Mekh. Astron. 8(66)(2) (2021), 331–337.

[18]   N. A. Rather, I. Dar and M. Shafi, On the zero bounds of polynomials and related analytic functions, Appl. Math. E-Notes 21 (2021), 525–532.

[19]   W. M. Shah and A, Liman, On Eneström-Kakeya theorem and related analytic functions, Proc. Indian Acad. Sci. 3 (2007), 359–370.