“…The first of them is the extraction (additive or multiplicative) of singularities from the discussed function, and the approximation of the function rest. The second one is an introduction of the mentioned singularities in the approximation apparatus (see [1], [4], [11], [22]). The second approach is usually simpler because it is required less than the priori information about the function in question (it is not required to know the exact function characteristics, its asymptotic behavior, orders of the defining multipliers, etc.)…”