常系数线性递推数列通项公式的矩阵求法

设数列为,若有正整数K和K＋1个实常数使对任意自然数n都成立,则称阶常系数线性递推数列,（l）式称为递推公式．彭咏松先生在文［l」中利用等比数列和线性方程组的一些知识,研究了常系数齐次（ho一O）线性递推数列的通项公式．本文利用矩阵理论讨论了一般的常系数线性速推数列通项公式．则（1）变为：将（2）式反复迭代,则有：当矩阵E－A可逆时,由于从而（3）式变为当时,,于是可见求数列（n｝通项公式的关键就是求矩阵A的n次方幂,利用矩阵理论可解决此问题．下面举例说明（X。）的通项公式的矩阵求法．例至已知X;一O,X。一1,…     

关于一类非常系数线性递推式的解的显式表示

本文给出了两个指标的非常系数的线性递推式的显式解。有关方法,避免了由于解高阶线性代数方程所带来的困难。其结果,为求解组合计数中相应定解问题,提供了一个明确的计算公式。     

递推序列的一个注记

我们给出变系数线性递推序列的一个算术性质，它类似于常系数线性递推序列的情形。     

m元线性递推数列与矩阵的幂

设有m个数列{x_n~(1),x_n~(2),…x_n~(n)}(这里x_n~(k)表示第k个数列的第n项)满足递推式组:■其中a_(ij)为常数(i,j=1,2,…,m),初始条件由x_1~(1),x_1~(2),…,x_1~(m)给定,这样的m个数列叫做m元线性递推数列。本文的工作是给出m元线性递推数列的通项公式的求解方法,同时得到矩阵的幂的一种计算方法。递推式组(1)可以用矩阵的形式表示为:     

常系数线性递推关系通项的求解

实例说明利用特征根法和生成函数法可求解常系数线性递推关系.并在此基础上给出常见的常系数线性非齐次递推关系通解的求法.     

竞赛中的递推数列问题

一般地，如果一个数列的第n项an与前面的k项a（n-1），a（n-2），…，a（n-l）（k为某个正整数，且k〈n）之间有关系an=f（a（n-1），a（n-2），，…，a（n-k）），则称该关系为k阶递推关系，或称为递归关系，这里厂是关于a（n-1），a（n-2），…，a（n-k）的k元函数，称为递推函数或递归函数。由k阶递推关系及给定的前k项a1，a2，…，ak的值（称为初始值）所确定的数列称为k阶递推数列或k阶递归数列．一阶、二阶递推数列是高中数学竞赛大纲要求的内容．     

二元变系数递推数列的求解

运用矩阵理论给出一类二元变系数递推数列的求解公式,此方法适用于变系数分式递推式及m元变系数递推式的求解问题。     

二阶非齐次递推式的构造性解法

但当f（n）≠0或p、q为n的函数即对于非齐次式或变系数递推式时将如何来解呢？由于这类问题在高考和数学竞赛中时有出现,为帮助学生开拓解题思路,本文介绍一种构造性解法,按f（n）的特点和根a、p的取值情况介绍如下：     

一类递推关系式的解的计算公式

文献[1]给出了一个三项单指标的常系数齐次递推式的一般解公式。本文一类带双指标的变系数非齐次递推关系的解的结构。其结果，对双指标的相应递推关系式的解的求出，亦或在其有关理论的研究方面，皆有其作用。     

关于双指标三项线性递推式的一般解

该文给出了一类双指标的三项线性递推式的一般解公式．有关结论，对具大数值双指标的相应速推式的解的求出，或在有关理论的研究方面，都有其作用．     

关于变系数线性方程的稳定性

本文给出了变系数线性方程有关稳定性的一些简洁的判据．对周期系数线性方程，给出了较为精确的渐近稳定性判据．从理论上解释了原先“冻结系数法”一般不能成立的原因．     

具有可测系数的二阶线性抛物型方程在高维区域的初—斜微商边值问题

Alkhutov,Manedov在[1]中讨论了具有可测系数的线性一致抛物型方程的Dirichlet问题,其中系数满足:这里k0,k1,p(＞n 2)是非负常数,本文讨论带有可测系数的一般线性一致抛物型方程的初-斜微商边值问题.     

Perturbed Recurrence Relations

In this paper, we give some new relations between two families of polynomials defined by three-term recurrence relations. These relations allow us to study how some properties of a family of orthogonal polynomials are affected when the coefficients of the recurrence relation are perturbed. In the literature some methods are already available. However, most of them are only effective for small perturbations. In order to show the sharpness of our method, we compare it with Gronwall's classical method in the case of large perturbations. Using our tool, we also give a relation between the differential equation satisfied by a family of orthogonal polynomials and its perturbed family. Some explicit results are obtained for Chebyshev polynomials of the second kind.     

Perturbed recurrence relations III the general case—some new applications

In this paper, we give some new extensions and some new applications of our results on the perturbation of coefficients and the order of a general recurrence relation—for example we will give some new results for the asymptotic properties, for the zeros and for the differential equations of the polynomials which satisfy the perturbed recurrence relation.      

Perturbed recurrence relations II the general case

In this paper, we give some new explicit relations between two families of polynomials defined by recurrence relations of all order. These relations allow us to analyze, even in the Sobolev case, how some properties of a family of orthogonal polynomials are affected when the coefficients of the recurrence relation and the order are perturbed. In a paper we have already given a method which allows us to study the polynomials defined by a three-term recurrence relation. Also here some generalizations are given.     

Recurrence Relations for the Coefficients in Series Expansions with Respect to Semi-Classical Orthogonal Polynomials

Let {P _k } be a sequence of the semi-classical orthogonal polynomials. Given a function f satisfying a linear second-order differential equation with polynomial coefficients, we describe an algorithm to construct a recurrence relation satisfied by the coefficients a _k [f] in f= _k a _k [f]P _k . A systematic use of basic properties (including some nonstandard ones) of the polynomials {P _k } results in obtaining a recurrence of possibly low order. Recurrences for connection or linearization coefficients related to the first associated generalized Gegenbauer, Bessel-type and Laguerre-type polynomials are given explicitly.     

On the recurrence coefficients of the generalized little q-Laguerre polynomials

In this paper we consider a semi-classical variation of the weight related to the little q-Laguerre polynomials and obtain a second order second degree discrete equation for the recurrence coefficients in the three-term recurrence relation.     

一类带双指标常系数齐次递推关系的显式解

本文推广了屠规彰＾［１］的结果，得到了一类带双指标的常系数齐次递推关系的一个明显解公式。有关结果，不论是在理论还是在实际方面，都有一定的意义。