HyperbolicInverseLangevinApproximationByKroger Method

Kröger's rational approximation of the inverse Langevin function (Kröger, M., J. Non-Newtonian Fluid Mech. 223 (2015) 77-87). Substantially more accurate than Cohen's Padé approximant (max. relative error ~0.28% vs. ~4.9%), at a similar computational cost, since it is still a single rational expression with only integer powers.

public static double InverseLangevinApproximationByKroger(
	double x
)