定积分计算的参数变换法

两种围道得到同一个含参数复函数定积分的表达式,一个表达式是带参数三角函数的定积分,另一个表达式是带参数的特殊函数.对参数进行积分和级数展开等操作,对比参数展开系数,得到了一些三角函数定积分的值.     

三角函数的定积分(Ⅱ)

由傅里叶级数展开法,得到了两类三角函数定积分的值.     

基于傅里叶级数的定积分计算技巧

对数三角函数可以在长度为π的区间上展开为傅里叶级数.通过交换积分和求和的次序,对数三角函数的定积分就转化为无穷求和形式,后者可以通过基本的求和方法求出.     

三角函数的定积分

利用围道积分和参数展开,得到了一类含三角函数定积分的值.     

用参数展开法计算一类反常积分

对含参数反常积分I(t,s)=∫+∞0 x-1(1+x)-sdx,由贝塔函数的积分表示得到I(t,s)的伽马函数表示,再由伽马函数的级数展开,得到I(t,s)的参数级数展开.I(t,s)可在积分符号内按参数展开,参数系数是含对数函数的反常积分.对比同类参数的系数,可得一系列含对数函数反常积分的值.     

对应函数D(z)和广义非正则方程

推广Riemann P函数的思想(用方程的参数表示方程所定义的函数),引入(?)函数统一表示正则积分和非正则积分.利用显式解讨论非Fuchs型方程的单值群.得到Floquet解的指标展开系数的显式.根据对应函数法统一研究广义非正则方程的求解问题,包括具有正则和非正则极点,本性奇点,代数,对数和超越奇点以及奇线的方程.利用(?)函数表示基本解系,从而推广解析理论的研究范围.指出(?)函数的自守性,并讨论Poincaré猜测的意义.     

利用改进的(G/G)-展开法求广义的(21)维 Boussinesq 方程的精确解

利用改进的(G /G)-展开法,求广义的(2+1)维 Boussinesq 方程的精确解,得到了该方程含有较多任意参数的用双曲函数、三角函数和有理函数表示的精确解,当双曲函数表示的行波解中参数取特殊值时,便得到广义的(2+1)维 Boussinesq 方程的孤立波解.     

利用改进的(G′/G)-展开法求广义的(2+1)维Boussinesq方程的精确解

利用改进的(G′/G)-展开法,求广义的(2+1)维Boussinesq方程的精确解,得到了该方程含有较多任意参数的用双曲函数、三角函数和有理函数表示的精确解,当双曲函数表示的行波解中参数取特殊值时,便得到广义的(2+1)维Boussinesq方程的孤立波解.     

基于结构元的模糊值函数曲面积分

针对扩张原理在模糊值函数曲面积分中的遍历性问题,结合实际应用背景给出了模糊值函数第一型曲面积分的概念及其结构元表示.通过将二维模糊点和模糊结构元的定义推广到三维空间中,给出了模糊值函数第二型曲面积分的定义及其结构元表示.研究结果不仅丰富了模糊分析学理论,而且为具有不确定性因素的工程实践提供了方法依据.     

一类二重积分的解法剖析及其推广

本文利用三角函数的性质分析并求解了一类二重积分,根据此二重积分中被积函数的对称性,将其推广到一类三重积分,得到了其积分值.     

Fourier analysis on trapezoids with curved sides

It is well known that smooth periodic functions can be expanded into Fourier series and can be approximated by trigonometric polynomials. The purpose of this paper is to do Fourier analysis for smooth functions on planar domains. A planar domain can often be divided into some trapezoids with curved sides, so first we do the Fourier analysis for smooth functions on trapezoids with curved sides. We will show that any smooth function on a trapezoid with curved sides can be expanded into Fourier sine series with simple polynomial factors, and so it can be well approximated by a combination of sine polynomials and simple polynomials. Then we consider the Fourier analysis on the global domain. Finally, we extend these results to the three-dimensional case.     

Representations for the derivative at zero and finite parts of the Barnes zeta function

We provide new representations for the finite parts at the poles and the derivative at zero of the Barnes zeta function in any dimension in the general case. These representations are in the forms of series and limits. We also give an integral representation for the finite parts at the poles. Similar results are derived for an associated function, which we term homogeneous Barnes zeta function. Our expressions immediately yield analogous representations for the logarithm of the Barnes gamma function, including the particular case also known as multiple gamma function.     

Inequalities for formal power series and entire functions

We present several integral and exponential inequalities for formal power series and for both arbitrary entire functions of exponential type and generalized Borel transforms. They are obtained through certain limit procedures which involve the multiparameter binomial inequalities, integral inequalities for continuous functions, and weighted norm inequalities for analytic functions. Some applications to the confluent hypergeometric functions, Bessel functions, Laguerre polynomials, and trigonometric functions are discussed. Also some generalizations are given.     

Series representations in the spirit of Ramanujan

Using an integral transform with a mild singularity, we obtain series representations valid for specific regions in the complex plane involving trigonometric functions and the central binomial coefficient which are analogues of the types of series representations first studied by Ramanujan over certain intervals on the real line. We then study an exponential type series rapidly converging to the special values of L-functions and the Riemann zeta function. In this way, a new series converging to Catalan?s constant with geometric rate of convergence less than a quarter is deduced. Further evaluations of some series involving hyperbolic functions are also given.     

基于李群方法的贝塞尔函数数学实现

基于李群的表示理论,首先讨论了欧拉群的表示及其性质;然后,从该群的表示理论出发,分别导出了第一类贝塞尔函数的积分形式和幂级数形式.该研究表明了群方法可以求解对称边界问题的解析波函数,并为用群方法求解电磁场问题创造了条件.     

Generalizing the Reciprocal Logarithm Numbers by Adapting the Partition Method for a Power Series Expansion

Recently, a novel method based on the coding of partitions was used to determine a power series expansion for the reciprocal of the logarithmic function, viz. z/ln (1+z). Here we explain how this method can be adapted to obtain power series expansions for other intractable functions. First, the method is adapted to evaluate the Bernoulli numbers and polynomials. As a result, new integral representations and properties are determined for the former. Then via another adaptation of the method we derive a power series expansion for the function z ^s /ln  ^s (1+z), whose polynomial coefficients A _k (s) are referred to as the generalized reciprocal logarithm numbers because they reduce to the reciprocal logarithm numbers when s=1. In addition to presenting a general formula for their evaluation, this paper presents various properties of the generalized reciprocal logarithm numbers including general formulas for specific values of s, a recursion relation and a finite sum identity. Other representations in terms of special polynomials are also derived for the A _k (s), which yield general formulas for the highest order coefficients. The paper concludes by deriving new results involving infinite series of the A _k (s) for the Riemann zeta and gamma functions and other mathematical quantities.     

Riemann boundary-value problem with index minus infinity on a rectifiable curve

The author investigates the piecewise-continuous Riemann boundary-value problem with index minus infinity on a closed rectifiable Jordan curve; the index of the problem is a measure of the integral effect exerted on the solvability of the problem by the argument and modulus of the coefficient, and also by the properties of the junction curve. Discontinuities of the second kind are admitted in the logarithm of the coefficient and in the free term. The solution of the problem is constructed explicitly in the class of functions having a weak power singularity.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 42, No. 10, pp. 1350–1356, October, 1990.     

Application of pseudo‐trigonometry to Bessel series and integrals of Bessel functions

In this article, an extension of the Laplace transform of J_n (t) to pseudo‐trigonometric function is discussed. We are seeking elementary functions expressed by Bessel series. It is shown that the result is applicable to the solution of the first‐order differential equation. The expression of modified Bessel integral formulas in pseudo‐trigonometric function is also discussed.