Monotonicity and convexity of the ratios of the first kind modified Bessel functions and applications

Let $I_{v}\left( x\right) $ be modified Bessel functions of the first kind. We prove the monotonicity property of the function $x\mapsto I_{u}\left( x\right) I_{v}\left( x\right) /I_{\left( u+v\right) /2}\left( x\right) ^{2}$ on $\left( 0,\infty \right) $. As a direct consequence, it deduces some kn...

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Detalles Bibliográficos
Autores: Yang Z-H., Zheng, S.
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2017
País:España
Institución:Basque Center for Applied Mathematics (BCAM)
Repositorio:BIRD. BCAM's Institutional Repository Data
OAI Identifier:oai:bird.bcamath.org:20.500.11824/698
Acceso en línea:http://hdl.handle.net/20.500.11824/698
Access Level:acceso embargado
Palabra clave:Modified Bessel functions of the first kind
Monotonicity
convexity
functional inequality
Turán type inequality
Descripción
Sumario:Let $I_{v}\left( x\right) $ be modified Bessel functions of the first kind. We prove the monotonicity property of the function $x\mapsto I_{u}\left( x\right) I_{v}\left( x\right) /I_{\left( u+v\right) /2}\left( x\right) ^{2}$ on $\left( 0,\infty \right) $. As a direct consequence, it deduces some known results including Tur\'{a}n-type inequalities and log-convexity or log-concavity of $I_{v}$ in $v$, as well as it yields some new and interesting monotonicity and convexity concerning the ratios of modified Bessel functions of the first kind. In addition, a few of sharp bounds involving $I_{v}\left( x\right) $ and their ratios are presented.