Asymptotics of some integrals involving modified Bessel and hyper-Bessel functions

Abstract

We investigate the asymptotic expansion of integrals analogous to Ball's integral \[\int_0^\infty \left(\frac{Γ(1+ν)|J_ν(x)|}{(x/2)^ν}\right)^{\!n}dx\] for large $n$ in which the Bessel function $J_{\nu }(x)$ is replaced by the modified Bessel functions $I_{\nu }(x)$ and $K_{\nu }(x)$ together with appropriate exponential factors $e^{\mp x}$, respectively. The above integral with $J_{\nu }(x)$ replaced by a hyper-Bessel function of the type recently discussed in Aktas {\it et al.} [The Ramanujan J., 2019] and taken over a finite interval determined by the first positive zero of the function is also considered for $n\to \infty$. We give the leading asymptotic behaviour of the hyper-Bessel function for $x\to +\infty$ in an appendix. Numerical examples are given to illustrate the accuracy of the various expansions obtained.

12 pages, 0 figures

References in corpus (1)

• Asymptotics of some generalised sine-integrals