A note on the asymptotics of the modified Bessel functions on the Stokes lines (1708.09656v2)

Abstract: We employ the exponentially improved asymptotic expansions of the confluent hypergeometric functions on the Stokes lines discussed by the author [Appl. Math. Sci. {\bf 7} (2013) 6601--6609] to give the analogous expansions of the modified Bessel functions $I_\nu(z)$ and $K_\nu(z)$ for large $z$ and finite $\nu$ on $\arg\,z=\pm\pi$ (and, in the case of $I_\nu(z)$, also on $\arg\,z=0$). Numerical results are presented to illustrate the accuracy of these expansions.