February 2015
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114 Reads
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46 Citations
Journal of Mathematical Analysis and Applications
In this paper, we prove that the double inequality \begin{equation*} 1+\alpha r'^2<\frac{\mathcal{K}_{a}(r)}{\sin(\pi a)\log(e^{R(a)/2}/r')}<1+\beta r'^2 \end{equation*} holds for all and if and only if and , where , is the generalized elliptic integral of the first kind and R(x) is the Ramanujan constant function. Besides, as the key tool, the series expression for the Ramanujan constant function R(x) is given.