ASYMPTOTIC EXPANSIONS OF INTEGRAL MEAN OF POLYGAMMA FUNCTIONS

被引:4
|
作者
Chen, Chao-Ping [1 ]
Elezovic, Neven [2 ]
Vuksic, Lenka [2 ]
机构
[1] Henan Polytech Univ, Sch Math & Informat, Jiaozuo City 454003, Henan Province, Peoples R China
[2] Univ Zagreb, Fac Elect Engn & Comp, Zagreb 10000, Croatia
来源
关键词
Gamma function; psi function; polygamma functions; Bernoulli numbers and polynomials; asymptotic expansion; GAMMA-FUNCTION; INEQUALITIES; DIGAMMA; BOUNDS;
D O I
10.7153/mia-18-19
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
Let s,t be two given real numbers, s not equal t and m is an element of N. We determine the coefficients a(j)(s,t) in the asymptotic expansion of integral (or differential) mean of polygamma functions Psi((m))(x) : 1/t - s integral(t)(s)Psi((m))(x + u) du similar to psi((m)) (x Sigma(infinity)(j=0) a(j)(s,t)/x(j)), x -> infinity. We derive the recursive relations for polynomials a(j)(t, s), and also as polynomials in intrinsic variables alpha = 1/2 (s + t - 1), beta = 1/4 [1 - (t - s)(2)]. We derive also the main properties of these polynomials and as a consequence the asymptotic formula for shifted variables.
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页码:255 / 266
页数:12
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