• 제목/요약/키워드: Psi and polygamma functions

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A DEFINITE INTEGRAL FORMULA

  • Choi, Junesang
    • East Asian mathematical journal
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    • 제29권5호
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    • pp.545-550
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    • 2013
  • A remarkably large number of integral formulas have been investigated and developed. Certain large number of integral formulas are expressed as derivatives of some known functions. Here we choose to recall such a formula to present explicit expressions in terms of Gamma function, Psi function and Polygamma functions. Some simple interesting special cases of our main formulas are also considered. It is also pointed out that the same argument can establish explicit integral formulas for other those expressed in terms of derivatives of some known functions.

INFINITE SERIES ASSOCIATED WITH PSI AND ZETA FUNCTIONS

  • KIM, YONGSUP
    • 호남수학학술지
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    • 제22권1호
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    • pp.53-60
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    • 2000
  • We evaluate some interesting families of infinite series expressed in terms of the Psi (or Digamma) and Zeta functions by analyzing the well-known identity associated with $_3F_2$ due to Watson. Some special cases are also considered.

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NEW CLASS OF INTEGRALS INVOLVING GENERALIZED HYPERGEOMETRIC FUNCTION AND THE LOGARITHMIC FUNCTION

  • Kim, Yongsup
    • 대한수학회논문집
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    • 제31권2호
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    • pp.329-342
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    • 2016
  • Motivated essentially by Brychkov's work [1], we evaluate some new integrals involving hypergeometric function and the logarithmic function (including those obtained by Brychkov[1], Choi and Rathie [3]), which are expressed explicitly in terms of Gamma, Psi and Hurwitz zeta functions suitable for numerical computations.

APPLICATION OF A CERTAIN FAMILY OF HYPERGEOMETRIC SUMMATION FORMULAS ASSOCIATED WITH PSI AND ZETA FUNCTIONS

  • Choi, June-Sang;H.M.Srivastava;Kim, Yong-Sup
    • 대한수학회논문집
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    • 제16권2호
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    • pp.319-332
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    • 2001
  • The main object of this paper is first to give tow contiguous analogues of a well-known hypergeometric summation formula for $_2$F$_1$(1/2). We then apply each of these analogues with a view to evaluating the sums of several classes of series in terms of Psi(or Digamma) and the Zeta functions. Relevant connections of the series identities presented here with those given elsewhere are also pointed out.

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INEQUALITIES AND COMPLETE MONOTONICITY FOR THE GAMMA AND RELATED FUNCTIONS

  • Chen, Chao-Ping;Choi, Junesang
    • 대한수학회논문집
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    • 제34권4호
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    • pp.1261-1278
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    • 2019
  • It is well-known that if ${\phi}^{{\prime}{\prime}}$ > 0 for all x, ${\phi}(0)=0$, and ${\phi}/x$ is interpreted as ${\phi}^{\prime}(0)$ for x = 0, then ${\phi}/x$ increases for all x. This has been extended in [Complete monotonicity and logarithmically complete monotonicity properties for the gamma and psi functions, J. Math. Anal. Appl. 336 (2007), 812-822]. In this paper, we extend the above result to the very general cases, and then use it to prove some (logarithmically) completely monotonic functions related to the gamma function. We also establish some inequalities for the gamma function and generalize some known results.

NOTE ON STIRLING POLYNOMIALS

  • Choi, Junesang
    • 충청수학회지
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    • 제26권3호
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    • pp.591-599
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    • 2013
  • A large number of sequences of polynomials and numbers have arisen in mathematics. Some of them, for example, Bernoulli polynomials and numbers, have been investigated deeply and widely. Here we aim at presenting certain interesting and (potentially) useful identities involving mainly in the second-order Eulerian numbers and Stirling polynomials, which seem to have not been given so much attention.

LOG-SINE AND LOG-COSINE INTEGRALS

  • Choi, Junesang
    • 호남수학학술지
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    • 제35권2호
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    • pp.137-146
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    • 2013
  • Motivated essentially by their potential for applications in a wide range of mathematical and physical problems, the log-sine and log-cosine integrals have been evaluated, in the existing literature on the subject, in many different ways. The main object of this paper is to present explicit evaluations of some families of log-sine and log-cosine integrals by making use of the familiar Beta function.

FURTHER LOG-SINE AND LOG-COSINE INTEGRALS

  • Choi, Junesang
    • 충청수학회지
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    • 제26권4호
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    • pp.769-780
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    • 2013
  • Motivated essentially by their potential for applications in a wide range of mathematical and physical problems, the log-sine and log-cosine integrals have been evaluated, in the existing literature on the subject, in many different ways. Very recently, Choi [6] presented explicit evaluations of some families of log-sine and log-cosine integrals by making use of the familiar Beta function. In the present sequel to the investigation [6], we evaluate the log-sine and log-cosine integrals involved in more complicated integrands than those in [6], by also using the Beta function.

CERTAIN INTEGRAL REPRESENTATIONS OF GENERALIZED STIELTJES CONSTANTS γk(a)

  • Shin, Jong Moon
    • East Asian mathematical journal
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    • 제31권1호
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    • pp.41-53
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    • 2015
  • A large number of series and integral representations for the Stieltjes constants (or generalized Euler-Mascheroni constants) ${\gamma}_k$ and the generalized Stieltjes constants ${\gamma}_k(a)$ have been investigated. Here we aim at presenting certain integral representations for the generalized Stieltjes constants ${\gamma}_k(a)$ by choosing to use four known integral representations for the generalized zeta function ${\zeta}(s,a)$. As a by-product, our main results are easily seen to specialize to yield those corresponding integral representations for the Stieltjes constants ${\gamma}_k$. Some relevant connections of certain special cases of our results presented here with those in earlier works are also pointed out.