Some best approximation formulas and inequalities for the Wallis ratio

Abstract

Abstract. In the paper, the authors establish some best approximation formulas and inequalities for Wallis ratio. These formulas and inequalities improve an approximation formula and a double inequality for Wallis ratio recently presented in "S. Guo, J.-G. Xu, and F. Qi, Some exact constants for the approximation of the quantity in the Wallis' formula,

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