The Watson-Nicholson formula gives an asymptotic expression for Hankel functions. Let be a Hankel
function of the first or second
kind, let
,
and define
Then
The Watson-Nicholson formula gives an asymptotic expression for Hankel functions. Let be a Hankel
function of the first or second
kind, let
,
and define
Then
Weisstein, Eric W. "Watson-Nicholson Formula." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Watson-NicholsonFormula.html