Abstract
In this paper our aim is to deduce some new results on the zeros of the derivatives of some Lommel and Struve functions of the first kind and to apply these results in order to determine the radii of convexity of some normalized Lommel and Struve functions of the first kind.
Similar content being viewed by others
References
Baricz, Á., Koumandos, S.: Turán type inequalities for some Lommel functions of the first kind. Proc. Edinb. Math. Soc. arXiv:1308.6477 (2014)
Baricz, Á., Szász, R.: The radius of convexity of normalized Bessel functions of the first kind. Anal. Appl. 12(5), 485–509 (2014)
Baricz, Á., Szász, R.: Close-to-convexity of some special functions and their derivatives. Bull. Malays. Math. Sci. Soc. arXiv:1402.0692 (2014)
Baricz, Á., Dimitrov, D.K., Mező, I.: Radii of starlikeness and convexity of some \(q\)-Bessel functions. arXiv:1409.0293 (2014)
Baricz, Á., Dimitrov, D.K., Orhan, H., Yağmur, N.: Radii of starlikeness of some special functions. arXiv:1406.3732 (2014)
Baricz, Á., Ponnusamy, S., Singh, S.: Turán type inequalities for Struve functions. arXiv:1401.1430 (2014)
Koumandos, S., Lamprecht, M.: The zeros of certain Lommel functions. Proc. Am. Math. Soc. 140, 3091–3100 (2012)
Levin, B.Ya.: Lectures on Entire Functions: Translation of Mathematics Monographs, vol. 150. American Mathematical Society, Providence (1996)
Orhan, H., Yağmur, N.: Geometric properties of generalized Struve functions. An. Ştiinţ. Univ. Al. I. Cuza Ia şi. Mat. (N.S.) (2014)
Pólya, G.: Über die Nullstellen gewisser ganzer Funktionen. Math. Z. 2, 352–383 (1918)
Skovgaard, H.: On inequalities of the Turán type. Math. Scand. 2, 65–73 (1954)
Steinig, J.: The real zeros of Struve’s function. SIAM J. Math. Anal. 1(3), 365–375 (1970)
Steinig, J.: The sign of Lommel’s function. Trans. Am. Math. Soc. 163, 123–129 (1972)
Watson, G.N.: A Treatise on the Theory of Bessel Functions. Cambridge University Press, Cambridge (1944)
Yağmur, N., Orhan, H.: Starlikeness and convexity of generalized Struve functions. Abstr. Appl. Anal. 2013: Art. 954513 (2013)
Acknowledgments
The work of both authors was initiated in September 2014 when they visited the Mathematics Department of Kafkas University in Kars, Turkey. Both authors are grateful to Murat Caǧlar, Erhan Deniz and Nizami Mustafa for their kind hospitality. The authors wish also to thank to the referee for his/her useful comments which enhanced this paper.
Author information
Authors and Affiliations
Corresponding author
Additional information
The research of Á. Baricz was supported by the Romanian National Authority for Scientific Research, CNCS-UEFISCDI, under Grant PN-II-RU-TE-2012-3-0190.
Rights and permissions
About this article
Cite this article
Baricz, Á., Yağmur, N. Geometric properties of some Lommel and Struve functions. Ramanujan J 42, 325–346 (2017). https://doi.org/10.1007/s11139-015-9724-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11139-015-9724-6
Keywords
- Lommel functions of the first kind
- Struve functions
- Univalent
- Starlike functions
- Radius of starlikeness
- Zeros of Lommel functions of the first kind
- Zeros of Struve functions
- Laguerre inequality