DOCSLIB.ORG

The Clausen Function Cl2(X) and Its Related Integrals

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Clausen Function Cl2(X) and Its Related Integrals Thai Journal of Mathematics Volume 12 (2014) Number 2 : 251{264 http://thaijmath.in.cmu.ac.th ISSN 1686-0209 The Clausen function Cl2(x) and its Related Integrals y z Junesang Choi and H. M. Srivastava ;1 yDepartment of Mathematics, Dongguk University, Gyeongju 780-714, Republic of Korea e-mail : [email protected] zDepartment of Mathematics and Statistics, University of Victoria, Victoria, British Columbia V8W 3R4, Canada e-mail : [email protected] Abstract : The Clausen function Cl2(x) arises in several applications. A large number of indefinite integrals of logarithmic or trigonometric functions can be expressed in closed form in terms of Cl2(x). The G-function introduced and sys- tematically investigated by Barnes in about 1900, which was revived in the middle of the 1980s in connection with the study of the determinants of the Laplacians, also has several useful and widely-spread applications. Here, in this paper, we aim at presenting some interesting definite integral formulas by using a known relationship between the Clausen function Cl2(x) and the Barnes G-function. Keywords : Clausen function Cl2(x); Barnes G-function; Catalan constant; Glaisher-Kinkelin constant; Euler-Mascheroni constant; Psi (or Digamma) func- tion ; Polygamma functions; Generalized zeta function; Riemann zeta function; Determinants of the Laplacians; Series involving the zeta functions. 2010 Mathematics Subject Classification : Primary 33B10, 33B15; Sec- ondary 11M06, 11M35. 1Corresponding author. Copyright ⃝c 2014 by the Mathematical Association of Thailand. All rights reserved. 252 Thai J. M ath. 12 (2014)/ J. Choi and H. M. Srivastava 1 Introduction, Definitions and Preliminaries Clausen's integral (or, synonymously, Clausen's function) Cl2(x) is defined by 1 Z [ ( )] X sin kx x 1 Cl (x) := = − log 2 sin η dη (x 2 R); (1.1) 2 k2 2 k=1 0 where R denotes the set of real numbers. This integral was first treated by Clausen in 1832 [1] and has since then been investigated by many authors (see, e.g.,[2], [3], [4], [5, Chapter 4], [6, Section 2.4], and many of the references cited therein). Some known properties and special values of the Clausen integral (or the Clausen function) include the periodic properties given by Cl2(2nπ ± θ) = Cl2(±θ) = ±Cl2(θ); (1.2) which, for n = 1 and with θ replaced by π + θ, yields Cl2(π + θ) = −Cl2(π − θ): (1.3) From the series definition (1.1), it is obvious that Cl2(nπ) = 0 (n 2 Z := f0; ±1; ±2; · · · g); (1.4) which, for n = 1; gives Z ( ) Z π 1 π=2 π log 2 sin θ dθ = 0 and log (sin θ) dθ = − log 2: (1.5) 0 2 0 2 1 Setting θ = 2 π in the series definition (1.1), and using the periodic property (1.3), we find that ( ) ( ) 1 3 Cl π = G = −Cl π ; (1.6) 2 2 2 2 where G is the Catalan constant defined by Z 1 X1 1 (−1)m ∼ G := K(κ)dκ = = 0:91596 55941 ··· ; (1.7) 2 (2m + 1)2 0 m=0 where K(κ) is the complete elliptic integral of the first kind given by Z π=2 dt K(κ) := p (jκj < 1): (1.8) 2 0 1 − κ2 sin t From (1.2), (1.3) and (1.4), it suffices to consider Cl2 (x) in the interval (0; π). The following special values of Cl2 (x) for arguments p π x = (p; q 2 N := f1; 2; 3;:::g) q The Clausen function Cl2(x) and its Related Integrals 253 were presented by Grosjean [3, p. 334, Eq. (12)] (see also Doelder [2]): ( ) [ ( ) ( )] ( ) Xq−1 p 1 0 r 0 r p Cl2 π = − 1 − sin r π q 4 q2 2q 2q q (1.9) ( r=1 ) q 2 N; p 2 f1; 2;:::; 2q − 1g;(p; q) = 1 ; where (and elsewhere in this paper) an empty sum is understood to be nil. For example, we have ( ) p [ ( ) ] 1 3 1 2 Cl π = 0 − π2 (1.10) 2 3 6 3 3 and ( ) [ ( ) ] 1 1 p 1 p p Cl π = 2 0 − 2( 2 + 1) π2 − 8(2 2 − 1) G ; (1.11) 2 4 32 8 where G is the Catalan constant given in (1.7). Here (z) denotes the Psi (or Digamma) function defined by Z d Γ0(z) z (z) := flog Γ(z)g = or log Γ(z) = (t) dt (1.12) dz Γ(z) 1 in terms of the familiar Gamma function Γ(z). The Polygamma functions (n)(z)(n 2 N) are defined by dn+1 dn (n)(z) := log Γ(z) = (z)(n 2 N ; z 2 C n Z−); (1.13) dzn+1 dzn 0 0 N N [ f g C Z− where 0 := 0 , and 0 denote the sets of nonnegative integers, com- plex numbers and nonpositive integers, respectively. In terms of the Hurwitz (or generalized) Zeta function ζ(s; a) defined by 1 X 1 ζ(s; a) := (<(s) > 1; a 2 C n Z−); (1.14) (k + a)s 0 k=0 we can write (n) − n+1 2 N 2 C n Z− (z) = ( 1) n! ζ(n + 1; z)(n ; z 0 ); (1.15) which may be used to deduce the properties of the Polygamma functions (n)(z)(n 2 N) from those of ζ(s; z)(s = n + 1; n 2 N) and vice versa. For example, in view of the relation (1.15), we find from (1.9), (1.10) and (1.11) that ( ) q−1 [ ( ) ( )] ( ) p 1 X r r p Cl2 π = ζ 2; − ζ 2; 1 − sin r π q 4 q2 2q 2q q (1.16) ( r=1 ) q 2 N; p 2 f1; 2;:::; 2q − 1g;(p; q) = 1 ; 254 Thai J. M ath. 12 (2014)/ J. Choi and H. M. Srivastava ( ) p [ ( ) ] π 3 1 2 π2 Cl = ζ 2; − (1.17) 2 3 6 3 3 and ( ) [ ( ) ] π 1 p 1 p p Cl = 2 ζ 2; − 2( 2 + 1) π2 − 8(2 2 − 1) G : (1.18) 2 4 32 8 The Riemann Zeta function ζ(s) is defined by 8 X1 X1 > 1 1 1 ( ) > = <(s) > 1 < ns 1 − 2−s (2n − 1)s ζ(s) := n=1 n=1 (1.19) > X1 − > 1 (−1)n 1 ( ) :> <(s) > 0; s =6 1 ; 1 − 21−s ns n=1 which, when compared with the definition in (1.14), yields ( ) − 1 ζ(s) = ζ(s; 1) = (2s − 1) 1 ζ s; = 1 + ζ(s; 2): (1.20) 2 The Clausen function Cl2(x) arises in several applications. A large number of indefinite integrals of logarithmic or trigonometric functions can be expressed in closed form in terms of Cl2(x) (see, e.g.,[5] and [7, Section 1.6]). The G-function introduced and systematically investigated by Barnes in about 1900 (see [8, 9, 10]), which was revived in about the middle of the 1980s in connection mainly with the study of the determinants of the Laplacians, also has several useful and widely- spread applications (see, e.g.,[6, Chapter 5]). Here, in our present investigation, we present some interesting definite integral formulas by using a known relationship between the Clausen function Cl2(x) and the Barnes G-function. 2 The Clausen function Cl2(x) and the Barnes G-function Barnes (see [8]; see also [6, Section 1.4]) defined the G-function satisfying each of the following properties: (a) G(z + 1) = Γ(z)G(z)(z 2 C); (b) G(1) = 1; (c) Asymptotically, ( ) n + 1 + z log G(z + n + 2) = log(2π) 2 ( ) n2 5 z2 + + n + + + (n + 1)z log n (2.1) 2 12 2 3n2 1 ( ) − − n − nz − log A + + O n−1 (n ! 1); 4 12 The Clausen function Cl2(x) and its Related Integrals 255 where A is the Glaisher-Kinkelin constant defined by ( ( ) ) Xn n2 n 1 n2 log A = lim k log k − + + log n + ; (2.2) n!1 2 2 12 4 k=1 the numerical value of A being given by ∼ A = 1:282427130 ··· : From this definition, Barnes [8] deduced several explicit Weierstrass canonical product forms of the G-function, one of which is recalled here in the following form: ( ) 1 z 1 1 2 G(z + 1) = (2π) 2 exp − z − (γ + 1)z 2 2 1 {( ) ( )} (2.3) Y z k z2 · 1 + exp −z + ; k 2k k=1 where γ denotes the Euler-Mascheroni constant defined by ! Xn 1 γ := lim − log n n!1 k k=1 ∼ = 0:57721 56649 01532 86060 65120 90082 40243 1042 ··· : (2.4) For later use, we recall each of the following known special values of the G- function (see [8] and [6, Section 1.4]): ( ) 1 1 − 1 1 − 3 G = 2 24 ·π 4 ·e 8 ·A 2 : (2.5) 2 (n!)n G(n + 2) = 1! 2! 3! ··· n! and G(n + 1) = (n 2 N): (2.6) 1·2·32·43 ··· nn−1 ( ) [ ( )]− 3 4 1 3 − G − 9 1 ∼ G = e 32 4π ·A 8 Γ = 0:293756 ··· (2.7) 4 4 and ( ) [ ( )] 1 4 3 − 1 − 1 3 + G − 9 1 ∼ G = 2 8 ·π 4 ·e 32 π ·A 8 Γ = 0:848718 ··· ; (2.8) 4 4 where ( ) 1 ∼ Γ = 3:62560 99082 21908 ··· : (2.9) 4 ( ) 3 G − 1 − 1 G ( 4 ) 8 · 4 · 2π 5 = 2 π e : (2.10) G 4 There is an interesting known relationship between the Clausen function Cl2(x) and the Barnes G-function, which is asserted by the following lemma (see, e.g.,[6, p.
Load more

Recommended publications
  • Limiting Values and Functional and Difference Equations †
    Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 17 February 2020 doi:10.20944/preprints202002.0245.v1 Peer-reviewed version available at Mathematics 2020, 8, 407; doi:10.3390/math8030407 Article Limiting values and functional and difference equations † N. -L. Wang 1, P. Agarwal 2,* and S. Kanemitsu 3 1 College of Applied Mathematics and Computer Science, ShangLuo University, Shangluo, 726000 Shaanxi, P.R. China; E-mail:[email protected] 2 Anand International College of Engineering, Near Kanota, Agra Road, Jaipur-303012, Rajasthan, India 3 Faculty of Engrg Kyushu Inst. Tech. 1-1Sensuicho Tobata Kitakyushu 804-8555, Japan; [email protected] * Correspondence: [email protected] † Dedicated to Professor Dr. Yumiko Hironaka with great respect and friendship Version February 17, 2020 submitted to Journal Not Specified Abstract: Boundary behavior of a given important function or its limit values are essential in the whole spectrum of mathematics and science. We consider some tractable cases of limit values in which either a difference of two ingredients or a difference equation is used coupled with the relevant functional equations to give rise to unexpected results. This involves the expression for the Laurent coefficients including the residue, the Kronecker limit formulas and higher order coefficients as well as the difference formed to cancel the inaccessible part, typically the Clausen functions. We also state Abelian results which yield asymptotic formulas for weighted summatory function from that for the original summatory function. Keywords: limit values; modular relation; Lerch zeta-function; Hurwitz zeta-function; Laurent coefficients MSC: 11F03; 01A55; 40A30; 42A16 1. Introduction There have appeared enormous amount of papers on the Laurent coefficients of a large class of zeta-, L- and special functions.
    [Show full text]
  • The Riemann and Hurwitz Zeta Functions, Apery's Constant and New
    The Riemann and Hurwitz zeta functions, Apery’s constant and new rational series representations involving ζ(2k) Cezar Lupu1 1Department of Mathematics University of Pittsburgh Pittsburgh, PA, USA Algebra, Combinatorics and Geometry Graduate Student Research Seminar, February 2, 2017, Pittsburgh, PA A quick overview of the Riemann zeta function. The Riemann zeta function is defined by 1 X 1 ζ(s) = ; Re s > 1: ns n=1 Originally, Riemann zeta function was defined for real arguments. Also, Euler found another formula which relates the Riemann zeta function with prime numbrs, namely Y 1 ζ(s) = ; 1 p 1 − ps where p runs through all primes p = 2; 3; 5;:::. A quick overview of the Riemann zeta function. Moreover, Riemann proved that the following ζ(s) satisfies the following integral representation formula: 1 Z 1 us−1 ζ(s) = u du; Re s > 1; Γ(s) 0 e − 1 Z 1 where Γ(s) = ts−1e−t dt, Re s > 0 is the Euler gamma 0 function. Also, another important fact is that one can extend ζ(s) from Re s > 1 to Re s > 0. By an easy computation one has 1 X 1 (1 − 21−s )ζ(s) = (−1)n−1 ; ns n=1 and therefore we have A quick overview of the Riemann function. 1 1 X 1 ζ(s) = (−1)n−1 ; Re s > 0; s 6= 1: 1 − 21−s ns n=1 It is well-known that ζ is analytic and it has an analytic continuation at s = 1. At s = 1 it has a simple pole with residue 1.
    [Show full text]
  • On the Values of a Class of Dirichlet Series at Rational Arguments
    PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY Volume 138, Number 4, April 2010, Pages 1223–1230 S 0002-9939(09)10171-5 Article electronically published on December 4, 2009 ON THE VALUES OF A CLASS OF DIRICHLET SERIES AT RATIONAL ARGUMENTS K. CHAKRABORTY, S. KANEMITSU, AND H.-L. LI (Communicated by Ken Ono) Dedicated to Professor Eiichi Bannai on his sixtieth birthday, with great respect and friendship Abstract. In this paper we shall prove that the combination of the gen- eral distribution property and the functional equation for the Lipschitz-Lerch transcendent capture the whole spectrum of deeper results on the relations be- tween the values at rational arguments of functions of a class of zeta-functions. By Theorem 1 and its corollaries, we can cover all the previous results in a rather simple and lucid way. By considering the limiting cases, we can also deduce new striking identities for Milnor’s gamma functions, among which is the Gauss second formula for the digamma function. 1. Introduction and the finite value case Srivastava [S2] (cf. also Srivastava and Choi [SC], pp. 336–344) gives two simpler proofs of interesting results of Cvijovi´c and Klinowski [CK1] on the finite expression for the values of a Bernoulli polynomial at rational arguments in terms of the values of the Hurwitz zeta-function at integer arguments with rational values for the perturbation. The first proof uses the Fourier series for the periodic Bernoulli polynomial and the formula for the decomposition into residue classes. The second proof uses the functional equation for the partial zeta-function q p 2Γ (s) πs 2πap a (1.1) ζ 1 − s, = cos − ζ s, q (2πq)s 2 q q a=1 ([SC, (8), p.
    [Show full text]
  • Identities for Catalan's Constant Arising from Integrals Depending
    Identities for Catalan’s constant arising from integrals depending on a parameter Federica Ferretti∗Alessandro Gambini†and Daniele Ritelli‡ Abstract In this paper we provide some relationships between Catalan’s constant and the 3F2 and 4F3 hypergeomet- ric functions, deriving them from some parametric integrals. In particular, using the complete elliptic integral of the first kind, we found an alternative proof of a result of Ramanujan for 3F2, a second identity related to 4F3 and using the complete elliptic integral of the second kind we obtain an identity by Adamchik. KEYWORD: Catalan constant, elliptic integral, hypergeometric functions. AMS SUBJECT CLASSIFICATION 33C75, 33C20 1 Introduction Catalan’s constant G was defined by Eug`ene Charles Catalan, who introduced this constant in [13, eq. (4) p. 23] as the alternating series ∞ ( 1)n G = ∑ − 2 . n=0 (2n + 1) It is well-known, [14, eq. (1) p. 1], that we may also express this constant with the following definite integral 1 arctan x dx. x Z0 This integral has stimulated the interest of Ramanujan, [23]. G was also identified by James W.L. Glaisher in 1877, see [17]. Its value is approximately G ∼= 0.915965594177 . and actually it is not known if it is a rational number. The constant G is somewhat ubiquitous since it appears in many occurrences connected to definite integrals or series summations; we give a (surely) non exhaustive list of papers that provide several interesting occurrences of G, including [1, 2, 7, 10, 15, 19, 22] and [26]. There are also interesting connections between Catalan’s constant and the Clausen’s integrals, that is arXiv:2005.04672v1 [math.CA] 10 May 2020 θ t Cl2(θ) = log 2 sin dt, − 0 2 Z the Hurwitz zeta function, Euler-Mascheroni constant and many other special functions, as one can see for instance in [10], [15], [26].
    [Show full text]
  • Special Functions Related to Dedekind Type DC-Sums and Their
    SPECIAL FUNCTIONS RELATED TO DEDEKIND TYPE DC-SUMS AND THEIR APPLICATIONS Yilmaz SIMSEK Akdeniz University, Faculty of Arts and Science, Department of Mathematics 07058 Antalya, Turkey [email protected] Abstract In this paper we construct trigonometric functions of the sum Tp(h, k), which is called Dedekind type DC-(Dahee and Changhee) sums. We establish analytic properties of this sum. We find trigonometric represen- tations 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 Tp(h, k). We also give some applications related to these sums and functions. 2000 Mathematics Subject Classification. 11F20, 11B68, 11M35, 11M41, 11S80, 33C10, 33E20. Key Words and Phrases. Dedekind sums, Hardy-Berndt sums, Bernoulli Functions, Euler Functions, Euler numbers and polynomials, Riemann zeta function, Hurwitz zeta function, Lerch zeta function, Dirichlet series for the polylogarithm function, Dirichlet’s eta function, Legendre chi function, trigonometric functions and generalized Lambert series. arXiv:0902.0380v1 [math.CV] 2 Feb 2009 1 Introduction, Definitions and Notations In this section, we give some definitions, notations and results related to the Dedekind sums. Firstly we start with the definition of the classical Dedekind sums. Let x [x] 1 , if x / Z ((x)) = − G − 2 ∈ 0, if x Z, ∈ 1 [x]G being the largest integer x. Let h and k be coprime integers with k > 0, the classical Dedekind sum≤ s(h, k) is defined as follows k−1 a ha s (h, k)= . k k a=1 X The reciprocity law of the classical Dedekind sums is given by 1 1 h k 1 s(h, k)+ s(k, h)= + + + , −4 12 k h hk where (h, k) = 1 and h, k N := 1, 2, 3, ..
    [Show full text]
  • Alternative Evaluation of a Ln Tan Integral Arising in Quantum Field
    Alternative evaluation of a lntan integral arising in quantum field theory Mark W. Coffey Department of Physics Colorado School of Mines Golden, CO 80401 (Received 2008) November 9, 2008 Abstract A certain dilogarithmic integral I7 turns up in a number of contexts in- cluding Feynman diagram calculations, volumes of tetrahedra in hyperbolic geometry, knot theory, and conjectured relations in analytic number theory. We provide an alternative explicit evaluation of a parameterized family of inte- grals containing this particular case. By invoking the Bloch-Wigner form of the dilogarithm function, we produce an equivalent result, giving a third evaluation of I7. We also alternatively formulate some conjectures which we pose in terms of values of the specific Clausen function Cl2. arXiv:0810.5077v2 [math-ph] 15 Nov 2008 Key words and phrases Clausen function, dilogarithm function, Hurwitz zeta function, functional equation, duplication formula, triplication formula AMS classification numbers 33B30, 11M35, 11M06 1 The particular integral 24 π/2 tan t + √7 I7 ln dt, (1) ≡ 7√7 π/3 tan t √7 Z − occurs in a number of contexts and has received significant attention in the last several years [3, 4, 5, 6]. This and related integrals arise in hyperbolic geometry, knot theory, and quantum field theory [6, 7, 8]. Very recently [9] we obtained an explicit evaluation of (1) in terms of the specific Clausen function Cl2. However, much work remains. This is due to the conjectured relation between a Dirichlet L series and I7 [6], ? ∞ 1 1 1 1 1 1 I7 = L 7(2) = + + . − "(7n + 1)2 (7n + 2)2 − (7n + 3)2 (7n + 4)2 − (7n + 5)2 − (7n + 6)2 # nX=0 (2) The ? here indicates that numerical verification to high precision has been per- formed but that no proof exists, the approximate numerical value of I being I 7 7 ≃ 1.15192547054449104710169.
    [Show full text]
  • The Barnes G-Function and the Catalan Constant
    Kyushu J. Math. 67 (2013), 105–116 doi:10.2206/kyushujm.67.105 THE BARNES G-FUNCTION AND THE CATALAN CONSTANT Xiaohan WANG (Received 24 December 2011 and revised 14 February 2012) Abstract. G = ∞ [(− )k/( n − )2] The Catalan constant, n=1 1 2 1 , has attracted much attention and has appeared in various contexts. It is the special value at s = 2oftheDirichletL- function associated with the Gaussian field with its character odd. In this paper, we appeal to the Barnes G-function and a form of the functional equation for the Riemann zeta-function, to deduce an expression for the integral in t/sin t and one for G. These give rise to a corollary which reveals the intrinsicity of the Catalan constant G to the Barnes G-function. We also use one of Ramanujan’s formulas to derive a theorem. 1. Introduction and statement of results Let ∞ ζ(s, a)= 1 , s = σ> (n + a)s Re 1 (1.1) n=0 denote the Hurwitz zeta-function whose special case is the Riemann zeta-function ∞ ζ(s)= ζ(s, ) = 1 ,σ>. 1 ns 1 (1.2) n=1 The Dirichlet L-function L(s, χ) associated with the Dirichlet character χ is defined by ∞ χ(n) L(s, χ) = ,σ>. ns 1 (1.3) n=1 The parity of χ is defined by the parity of a in χ(−1) = (−1)a and χ is called even or odd according to whether a is even or odd. Hence, − χ(− ) 0 χ even a = a(χ) = 1 1 = 2 1 χ odd.
    [Show full text]
  • Computation and Structure of Character Polylogarithms with Applications to Character Mordell–Tornheim–Witten Sums
    Computation and structure of character polylogarithms with applications to character Mordell{Tornheim{Witten sums D. H. Bailey∗ J. M. Borwein.y June 9, 2014 Abstract This paper extends tools developed in [10,8] to study character polylogarithms. These objects are used to compute Mordell-Tornheim-Witten character sums and to explore their connections with multiple-zeta values (MZVs) and with their character analogues [17]. 1 Introduction In [10] we defined an ensemble of extended Mordell{Tornheim{Witten (MTW) zeta func- tion values [18, 34, 24, 25,7, 12, 36, 38, 32]. There is by now a huge literature on these sums; in part because of the many connections with fields such as combinatorics, number theory, and mathematical physics. Unlike previous authors we included derivatives with re- spect to the order of the terms. We investigated interrelations amongst MTW evaluations, and explored some deeper connections with multiple-zeta values (MZVs). In this article we continue the research in [8, 10] by studying character polylogarithms and applying them to analyze the relations between MTW character sums defined by X χd1(m) χd2(n) 1 µ (q; r; s) := ; (1) d1;d2 mq nr (m + n)s n;m>0 ±d n−1 where for d > 2, χ±d(n) := n ; and χ−2(n) := (−1) ; χ1(n) = 1: When d1 = d2 = 1 these devolve to classical Mordell{Tornheim{Witten (MTW) sums, as defined in (2) below for K = 2. ∗Lawrence Berkeley National Lab (retired), Berkeley, CA 94720, and University of California, Davis, Dept. of Computer Science, Davis, CA 95616, USA. E-mail: [email protected].
    [Show full text]
  • Log-Sine Integrals Involving Series Associated with the Zeta Function and Polylogarithms
    MATH. SCAND. 105 (2009), 199–217 LOG-SINE INTEGRALS INVOLVING SERIES ASSOCIATED WITH THE ZETA FUNCTION AND POLYLOGARITHMS JUNESANG CHOI, YOUNG JOON CHO and H. M. SRIVASTAVA Abstract Motivated essentially by their potential for applications in a wide range of mathematical and physical problems, the Log-Sine integrals have been evaluated, in the existing literature on the subject, in many different ways. The main object of this paper is to show how nicely some general (m) π formulas analogous to the generalized Log-Sine integral Lsn 3 can be obtained by using the theory of Polylogarithms. Relevant connections of the results presented here with those obtained in earlier works are also indicated precisely. 1. Introduction and Preliminaries Motivated essentially by their potential for applications in a wide range of mathematical and physical problems, the Log-Sine integrals have been eval- uated, in the existing literature on the subject, in many different ways. Here, we mainly aim at showing how nicely some general formulas analogous to the (m) π generalized Log-Sine integral Lsn 3 can be obtained by using the theory of Polylogarithms. We also give remarks on some related results on this subject. For our purpose, we begin by recalling the following definitions and prop- erties, which will be needed in our investigation. Definition 1. The Log-Sine integrals Lsn(θ) of order n are defined by (1.1) θ x n−1 Lsn(θ) :=− log 2 sin dx (n ∈ N \{1}; N :={1, 2, 3,...}); 0 2 (m) The generalized Log-Sine integrals Lsn (θ) of order n and index m are defined by θ n−m− (m) m x 1 (1.2) Lsn (θ) :=− x log 2 sin dx 0 2 Received July 14, 2008.
    [Show full text]
  • New Integral Representations of the Polylogarithm Function
    New integral representations of the polylogarithm function Djurdje Cvijović1 1 Atomic Physics Laboratory, Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade, Serbia. Abstract. Maximon has recently given an excellent summary of the properties of the Euler dilogarithm function and the frequently used generalizations of the dilogarithm, the most important among them being the polylogarithm function Lis () z . The polylogarithm function appears in several fields of mathematics and in many physical problems. We, by making use of elementary arguments, deduce several new integral representations of the polylogarithm Lis () z for any complex z for which z < 1. Two are valid for all complex s, whenever Res > 1. The other two involve the Bernoulli polynomials and are valid in the important special case where the parameter s is an positive integer. Our earlier established results on the integral representations for the Riemann zeta function ζ (2n + 1) , nN∈ , follow directly as corollaries of these representations. Keywords: Polylogarithms, integral representation, Riemann’s zeta function, Bernoulli polynomials 2000 Mathematics Subject Classification. Primary 11M99; Secondary 33E20. 1 1. Introduction Recently, Maximon [1] has given an excellent summary of the defining equations and properties of the Euler dilogarithm function and the frequently used generalizations of the dilogarithm, the most important among them being the polylogarithm function Lis () z . These include integral representations, series expansions, linear and quadratic transformations, functional relations and numerical values for special arguments. Motivated by this paper we have begun a systematic study of new integral representations for Lis () z since it appears that only half a dozen of them can be found in the literature.
    [Show full text]
  • An Efficient Calculation of the Clausen Functions Cln(Θ)
    BIT Numer Math (2010) 50: 193–206 DOI 10.1007/s10543-009-0246-8 An efficient calculation of the Clausen functions Cln(θ)(n ≥ 2) Jiming Wu · Xiaoping Zhang · Dongjie Liu Received: 3 August 2009 / Accepted: 3 December 2009 / Published online: 16 December 2009 © Springer Science + Business Media B.V. 2009 Abstract The Clausen functions appear in many problems, such as in the computa- tion of singular integrals, quantum field theory, and so on. In this paper, we consider the Clausen functions Cln(θ) with n ≥ 2. An efficient algorithm for evaluating them is suggested and the corresponding convergence analysis is established. Finally, some numerical examples are presented to show the efficiency of our algorithm. Keywords Clausen functions · Error estimate Mathematics Subject Classification (2000) 65R99 · 65G20 · 65B10 1 Introduction In many occasions, such as in the evaluation of singular integrals [1, 4, 6, 8, 14, 15, 17] and quantum field theory [5, 7, 9], it is often necessary to compute the Clausen Communicated by Lothar Reichel. J. Wu Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beijing 100088, P.R. China e-mail: [email protected] X. Zhang () School of Mathematics and Statistics, Wuhan University, Wuhan 430072, P.R. China e-mail: [email protected] D. Liu Department of Mathematics, College of Sciences, Shanghai University, Shanghai 200444, P.R. China e-mail: [email protected] 194 J. Wu et al. functions, defined by ∞ sin(kθ) = n ,neven, Cl (θ) = k 1 k (1.1) n ∞ cos(kθ) k=1 kn ,nodd.
    [Show full text]
  • Evaluation of a Ln Tan Integral Arising in Quantum Field Theory
    Evaluation of a lntan integral arising in quantum field theory Mark W. Coffey Department of Physics Colorado School of Mines Golden, CO 80401 (Received 2007) August 27, 2007 Abstract We analytically evaluate a dilogarithmic integral that is prototypical of volumes of ideal tetrahedra in hyperbolic geometry. We additionally obtain new representations of the Clausen function Cl2 and the Catalan constant G = Cl2(π/2), as well as new relations between sine and Clausen function values. arXiv:0801.0272v1 [math-ph] 1 Jan 2008 Key words and phrases Clausen function, trigamma function, polygamma function, dilogarithm function, Hurwitz zeta function AMS classification numbers 33B30, 33B15, 11M35 1 Introduction and statement of results In this paper, we provide a closed form evaluation of the integral 24 π/2 tan t + √7 I7 ln dt, (1.1) ≡ 7√7 π/3 tan t √7 Z − in terms of elementary mathematical constants and values of the Clausen function Cl2. This and related integrals originate in hyperbolic geometry and quantum field theory [7, 14]. The integral I7 arises in the analysis of the volume of ideal tetrahedra in hyperbolic space and is the simplest of 998 empirically investigated cases wherein the volume of a hyperbolic knot complement appears to be expressible in terms of a Dirichlet L series [5]. In particular, Borwein and Broadhurst have conjectured that ? ∞ 1 1 1 1 1 1 I7 = L 7(2) = + + . − "(7n + 1)2 (7n + 2)2 − (7n + 3)2 (7n + 4)2 − (7n + 5)2 − (7n + 6)2 # nX=0 (1.2) The ? here indicates numerical verification has been performed but that no proof exists.
    [Show full text]