A new asymptotic expansion and sharp inequality for the volume of the unit ball in R^n

Abstract

For n ∈ { 1 , 2 , . . . } , let Ω n = π n/ 2 / Γ( n 2 + 1) be the volume of the unit ball in R n . In this paper, we give a new asymptotic expansion for Ω n . Based on the obtained result, we also establish a sharp double inequality for Ω n .