Inequalities concerning polar derivative of polynomials

Arty Ahuja; K. K. Dewan; Sunil Hans

Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica (2011)

  • Volume: 65, Issue: 1
  • ISSN: 0365-1029

Abstract

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In this paper we obtain certain results for the polar derivative of a polynomial p ( z ) = c n z n + j = μ n c n - j z n - j , 1 μ n , having all its zeros on | z | = k , k 1 , which generalizes the results due to Dewan and Mir, Dewan and Hans. We also obtain certain new inequalities concerning the maximum modulus of a polynomial with restricted zeros. [Editor’s note: There are flaws in the paper, see M. A. Qazi, Remarks on some recent results about polynomials with restricted zeros, Ann. Univ. Mariae Curie-Skłodowska Sect. A 67 (2), (2013), 59-64 ]

How to cite

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Arty Ahuja, K. K. Dewan, and Sunil Hans. "Inequalities concerning polar derivative of polynomials." Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica 65.1 (2011): null. <http://eudml.org/doc/289768>.

@article{ArtyAhuja2011,
abstract = {In this paper we obtain certain results for the polar derivative of a polynomial $p(z) = c_nz^n +\sum _\{j=\mu \}^n c_\{n-j\}z^\{n-j\}$, $1\le \mu \le n$, having all its zeros on $|z| = k$, $k\le 1$, which generalizes the results due to Dewan and Mir, Dewan and Hans. We also obtain certain new inequalities concerning the maximum modulus of a polynomial with restricted zeros. [Editor’s note: There are flaws in the paper, see M. A. Qazi, Remarks on some recent results about polynomials with restricted zeros, Ann. Univ. Mariae Curie-Skłodowska Sect. A 67 (2), (2013), 59-64 ]},
author = {Arty Ahuja, K. K. Dewan, Sunil Hans},
journal = {Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica},
keywords = {Polynomials; maximum modulus; inequalities in the complex domain; polar derivative},
language = {eng},
number = {1},
pages = {null},
title = {Inequalities concerning polar derivative of polynomials},
url = {http://eudml.org/doc/289768},
volume = {65},
year = {2011},
}

TY - JOUR
AU - Arty Ahuja
AU - K. K. Dewan
AU - Sunil Hans
TI - Inequalities concerning polar derivative of polynomials
JO - Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica
PY - 2011
VL - 65
IS - 1
SP - null
AB - In this paper we obtain certain results for the polar derivative of a polynomial $p(z) = c_nz^n +\sum _{j=\mu }^n c_{n-j}z^{n-j}$, $1\le \mu \le n$, having all its zeros on $|z| = k$, $k\le 1$, which generalizes the results due to Dewan and Mir, Dewan and Hans. We also obtain certain new inequalities concerning the maximum modulus of a polynomial with restricted zeros. [Editor’s note: There are flaws in the paper, see M. A. Qazi, Remarks on some recent results about polynomials with restricted zeros, Ann. Univ. Mariae Curie-Skłodowska Sect. A 67 (2), (2013), 59-64 ]
LA - eng
KW - Polynomials; maximum modulus; inequalities in the complex domain; polar derivative
UR - http://eudml.org/doc/289768
ER -

References

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  1. Bernstein, S., Lecons sur les proprietes extremales et la meilleure approximation desfonctions analytiques d’une variable reele, Gauthier Villars, Paris, 1926 (French). 
  2. Chan, T. N., Malik, M. A., On Erdos-Lax theorem, Proc. Indian Acad. Sci. 92 (3) (1983), 191-193. 
  3. Dewan, K. K., Hans, S., On maximum modulus for the derivative of a polynomial, Ann. Univ. Mariae Curie-Skłodowska Sect. A 63 (2009), 55-62. 
  4. Dewan, K. K., Mir, A., Note on a theorem of S. Bernstein, Southeast Asian Bulletin of Math. 31 (2007), 691-695. 
  5. Govil, N. K., On the theorem of S. Bernstein, J. Math. Phys. Sci. 14 (1980), 183-187. 
  6. Govil, N. K., Rahman, Q. I., Functions of exponential type not vanishing in a half plane and related polynomials, Trans. Amer. Math. Soc. 137 (1969), 501-517. 
  7. Jain, V. K., On polynomials having zeros in closed exterior or interior of a circle, Indian J. Pure Appl. Math. 30 (1999), 153-159. 
  8. Malik, M. A., On the derivative of a polynomial, J. London Math. Soc. 1 (1969), 57-60. 
  9. Mir, A., On extremal properties and location of zeros of polynomials, Ph.D. Thesis submitted to Jamia Millia Islamia, New Delhi, 2002. 
  10. Qazi, M. A., On the maximum modulus of polynomials, Proc. Amer. Math. Soc. 115 (1992), 337-343. 

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