Now showing items 1-6 of 6

    • Convergent expansions of the Bessel functions in terms of elementary functions 

      López García, José Luis Upna Orcid; Pagola Martínez, Pedro Jesús Upna (Springer US, 2018)   Artículo / Artikulua  OpenAccess
      We consider the Bessel functions Jν (z) and Yν (z) for ν > −1/2 and z ≥ 0. We derive a convergent expansion of Jν (z) in terms of the derivatives of (sin z)/z, and a convergent expansion of Yν (z) in terms of derivatives ...
    • Convergent expansions of the incomplete gamma functions in terms of elementary functions 

      Bujanda Cirauqui, Blanca Upna Orcid; López García, José Luis Upna Orcid; Pagola Martínez, Pedro Jesús Upna (World Scientific Publishing, 2017)   Artículo / Artikulua  OpenAccess
      We consider the incomplete gamma function γ(a,z) for Ra>0 and z∈C. We derive several convergent expansions of z−aγ(a,z) in terms of exponentials and rational functions of z that hold uniformly in z with Rz bounded from ...
    • Uniform convergent expansions of integral transforms 

      López García, José Luis Upna Orcid; Palacios Herrero, Pablo; Pagola Martínez, Pedro Jesús Upna (American Mathematical Society, 2021)   Artículo / Artikulua  OpenAccess
      Several convergent expansions are available for most of the special functions of the mathematical physics, as well as some asymptotic expansions [NIST Handbook of Mathematical Functions, 2010]. Usually, both type of ...
    • Uniform convergent expansions of the Gauss hypergeometric function in terms of elementary functions 

      Ferreira González, Chelo Upna; López García, José Luis Upna Orcid; Pérez Sinusía, Ester Upna Orcid (Taylor & Francis, 2018)   Artículo / Artikulua  OpenAccess
      We consider the hypergeometric function 2F1(a, b; c; z) for z ∈ C \ [1,∞). For Ra ≥ 0, we derive a convergent expansion of 2F1(a, b; c; z) in terms of the function (1 − z)−a and of rational functions of z that is uniformly ...
    • Uniform representation of the incomplete beta function in terms of elementary functions 

      Ferreira González, Chelo Upna; López García, José Luis Upna Orcid; Pérez Sinusía, Ester Upna Orcid (Kent State UniversityJohann Radon Institute (RICAM), 2018)   Artículo / Artikulua  OpenAccess
      We consider the incomplete beta function Bz(a, b) in the maximum domain of analyticity of its three variables: a, b, z ∈ C, −a /∈ N, z /∈ [1, ∞). For <b ≤ 1 we derive a convergent expansion of z−aBz(a, b) in terms of the ...
    • Uniformly convergent expansions for the generalized hypergeometric functions p –1Fp and pFp 

      López García, José Luis Upna Orcid; Pagola Martínez, Pedro Jesús Upna; Karp, D. B. (Taylor & Francis, 2020)   Artículo / Artikulua  OpenAccess
      We derive a convergent expansion of the generalized hypergeometric function p−1 F p in terms of the Bessel functions 0 F 1 that holds uniformly with respect to the argument in any horizontal strip of the complex plane. We ...