Closed-form formulae for the derivatives of trigonometric functions at rational multiples of π\pi

In this sequel to our recent note it is shown, in a unified manner, by making use of some basic properties of certain special functions, such as the Hurwitz zeta function, Lerch zeta function and Legendre chi function, that the values of all derivatives of four trigonometric functions at rational multiples of $\pi$ can be expressed in closed form as simple finite sums involving the Bernoulli and Euler polynomials. In addition, some particular cases are considered.Comment: 5 page

New properties of the Lerch's transcendent

A new representation of the Lerch''s transcendent F(z, s, a), valid for positive integer s=n=1, 2, … and for z and a belonging to certain regions of the complex plane, is presented. It allows to write an equation relating F(z, n, a) and F(1/z, n, 1-a), which in turn provides an expansion of F(z, n, a) as a power series of 1/z, convergent for |z|>1

Some discrete Fourier transform pairs associated with the Lipschitz-Lerch Zeta function

It is shown that there exists a companion formula to Srivastavas formula for the Lipschitz-Lerch Zeta function [see H.M. Srivastava, Some formulas for the Bernoulli and Euler polynomials at rational arguments, Math. Proc. Cambridge Philos. Soc. 129 (2000) 77-84] and that together these two results form a discrete Fourier transform pair. This Fourier transform pair makes it possible for other (known or new) results involving the values of various Zeta functions at rational arguments to be easily recovered or deduced in a more general context and in a remarkably unified manner. (C) 2009 Elsevier Ltd. All rights reserved

Integral representations of the Legendre chi function

We, by making use of elementary arguments, deduce integral representations of the Legendre chi function chi(S)(z) valid for vertical bar z vertical bar LT 1 and Res GT 1. Our earlier established results on the integral representations for the Riemann zeta function zeta(2n + 1) and the Dirichlet beta function beta(2n), n epsilon N, are a direct consequence of these representations. (c) 2006 Elsevier Inc. All rights reserved

Reflection properties of zeta related functions in terms of fractional derivatives

We prove that the Weyl fractional derivative is a useful instrument to express certain properties of the zeta related functions. Specifically, we show that a known reflection property of the Hurwitz zeta function ¿(n, a) of integer first argument can be extended to the more general case of ¿(s, a), with complex s, by replacement of the ordinary derivative of integer order by Weyl fractional derivative of complex order. Besides, ¿(s, a) with (s) > 2 is essentially the Weyl (s-2)-derivative of ¿(2, a). These properties of the Hurwitz zeta function can be immediately transferred to a family of polygamma functions of complex order defined in a natural way. Finally, we discuss the generalization of a recently unveiled reflection property of the Lerch''s transcendent

Numerical Approximation of Some Infinite Gaussian Series and Integrals

The paper deals with numerical computation of the asymptotic variance of the so-called increment ratio (IR) statistic and its modifications. The IR statistic is useful for estimation and hypothesis testing on fractional parameter H ∈ (0, 1) of random process (time series), see Surgailis et al. [1], Bardet and Surgailis [2]. The asymptotic variance of the IR statistic is given by an infinite integral (or infinite series) of 4-dimensional Gaussian integrals which depend on parameter H. Our method can be useful for numerical computation of other similar slowly convergent Gaussian integrals/series. Graphs and tables of approximate values of the variances σp2(H) and σˆp2(H), p = 1, 2 are included

Special Functions Related to Dedekind Type DC-Sums and their Applications

In this paper we construct trigonometric functions of the sum T_{p}(h,k), which is called Dedekind type DC-(Dahee and Changhee) sums. We establish analytic properties of this sum. We find trigonometric representations of this sum. We prove reciprocity theorem of this sums. Furthermore, we obtain relations between the Clausen functions, Polylogarithm function, Hurwitz zeta function, generalized Lambert series (G-series), Hardy-Berndt sums and the sum T_{p}(h,k). We also give some applications related to these sums and functions