Computational & Applied Mathematics
On-line version ISSN 1807-0302
CHEN, Chao-Ping and MORTICI, Cristinel. Sharpness of Muqattash-Yahdi problem. Comput. Appl. Math. [online]. 2012, vol.31, n.1, pp. 85-93. ISSN 1807-0302. http://dx.doi.org/10.1590/S1807-03022012000100005.
Let ψ denote the psi (or digamma) function. We determine the values of theparameters p, q and r such that ψ(n) ≈ ln(n + p) - is the best approximations. Also, we present closer bounds for psi function, which sharpens some known results due to Muqattash and Yahdi, Qi and Guo, and Mortici. Mathematical subject classification: 33B15, 26D15.
Keywords : psi function; polygamma functions; rate of convergence; approximations.