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If we restrict ourselves to the class of polynomials having no zeros in |z| then inequality ( ) can be sharpened. In fact it was shown by Ankeny and Rivlin, - that if p(z) in |z| then ( ) can be replaced by
By involving the coefficients of p(z) Dewan and Ahuja , - in the same paper obtained the following refinement of Theorem A.
Theorem B.. If ( ) ∑is a polynomial of degree n having all its zeros on| | ? ? then for every positive integer s*?( ?)+?
In this paper we restrict ourselves to the class of polynomials of degree n having all its zeros on |z| k k and obtain an improvement and generalization of Theorem A and Theorem B. More precisely we prove Theorem .. If ( ) ∑is a polynomial of degree n having all its zeros on| | ? ? then for every positive integer s and R
For the proof of these theorems we need the following lemmas. Lemma .. If ( ) ∑?? ? ? is a polynomial of degree having all its zeros on| | ? ? then
From which we get the desired result.
The proof of inequality ( ) follows on the same lines as that of inequality (9) but instead of using inequality ( 5) of Lemma 3 we use inequality ( 6) of Lemma 3.
REFERENCES
[1] Ankeny N. C. & Rivlin T. J. ( 955). On a theorem of S. Bernstein. Pacific J. Math. 5 849-85 .
[2] Dewan K. K. & Ahuja A. ( ). Growth of polynomials with prescribed zeros. Journal of Mathematical Inequalities 5(3) 355-36 .
[3] Govil N. K. ( 98 ). On the theorem of S. Bernstein. J. Math.and Phy.Sci. 4 83- 87.
[4] Polya G. & Szego G. ( 9 5). Aufgabed and Lehrsatze aus der analysis. Berlin: Springer-Verlag.
[5] Dewan K. K. & Mir A. ( 7). Note on a theorem of S. Bernstein. Southeast Asian Bulletin of Math. 3 69 -695.
[6] Frapier C. Rahman Q. I. & Ruscheweyh St. ( 985). New inequalities for polynomials. Trans. Amer. Math. Soc. 88 69-99.
By involving the coefficients of p(z) Dewan and Ahuja , - in the same paper obtained the following refinement of Theorem A.
Theorem B.. If ( ) ∑is a polynomial of degree n having all its zeros on| | ? ? then for every positive integer s*?( ?)+?
In this paper we restrict ourselves to the class of polynomials of degree n having all its zeros on |z| k k and obtain an improvement and generalization of Theorem A and Theorem B. More precisely we prove Theorem .. If ( ) ∑is a polynomial of degree n having all its zeros on| | ? ? then for every positive integer s and R
For the proof of these theorems we need the following lemmas. Lemma .. If ( ) ∑?? ? ? is a polynomial of degree having all its zeros on| | ? ? then
From which we get the desired result.
The proof of inequality ( ) follows on the same lines as that of inequality (9) but instead of using inequality ( 5) of Lemma 3 we use inequality ( 6) of Lemma 3.
REFERENCES
[1] Ankeny N. C. & Rivlin T. J. ( 955). On a theorem of S. Bernstein. Pacific J. Math. 5 849-85 .
[2] Dewan K. K. & Ahuja A. ( ). Growth of polynomials with prescribed zeros. Journal of Mathematical Inequalities 5(3) 355-36 .
[3] Govil N. K. ( 98 ). On the theorem of S. Bernstein. J. Math.and Phy.Sci. 4 83- 87.
[4] Polya G. & Szego G. ( 9 5). Aufgabed and Lehrsatze aus der analysis. Berlin: Springer-Verlag.
[5] Dewan K. K. & Mir A. ( 7). Note on a theorem of S. Bernstein. Southeast Asian Bulletin of Math. 3 69 -695.
[6] Frapier C. Rahman Q. I. & Ruscheweyh St. ( 985). New inequalities for polynomials. Trans. Amer. Math. Soc. 88 69-99.