The diagonal Pade' approximates for exp(x).tan x and tanh x are obtained in a simple manner by using the property of Legendre polynomials that on [-1,1] Pn(x) is orthogonal to every polynomial of lower degree.Gauss's quadrature formula is used tofined the denomiators of some functions.
G.A.Baker,Jr.,Essentials of Pade' Approximants,Academic Press(1975).
[2]
W.B.Jones and W.J.Thron,Continued Fractions:Analytic Theory and Applications,Encyclopedia of Mathematics and its Applications Ⅱ,Addison Wesley Publ.Co.(1980).
[3]
E.B.Saff and R.S.Varga(Editors),Pade' and Rational Approximation,Academic Press(1977).