Some Padé approximations and inequalities for the complete elliptic integrals of the first kind

Abstract

AbstractIn this paper, we present Padé approximations of some functions involving complete elliptic integrals of the first kind $K(x)$ K ( x ) , and motivated by these approximations we also present the following double inequality: $$ \frac{1-x^{2}}{1-x^{2}+\frac{x^{4}}{62}}< \frac{2 e^{\frac{2}{\pi }K(x)-1}}{ (1+\frac{1}{\sqrt{1-x^{2}}} )}< \frac{1-\frac{96}{100}x^{2}}{1-\frac{96}{100}x^{2}+\frac{x^{4}}{64}},\quad x\in ( 0,1 ). $$ 1 − x 2 1 − x 2 + x 4 62 < 2 e 2 π K ( x ) − 1 ( 1 + 1 1 − x 2 ) < 1 − 96 100 x 2 1 − 96 100 x 2 + x 4 64 , x ∈ ( 0 , 1 ) . Our results have superiority over some new recent results.