数列的循环求和法——探索一类数列和的表达式

数列求和的方法很多,己有许多杂志刊登了各种数列求和方法的文章,本文提及的循环求和法,其思想方法是通过式子变形,使所求和重复出现,造成循环,亦即构造出含有所求和S的方程S=f(s),然后解出S。问题:求 sum from k=1 to n (k·2~k)sum from k=1 to n (k·2~k)=sum from k=0 to (n-1) ((k+1)2~(k+1))=2 sum from k=0 to (n-1) k2~k+sum from k= to (n-1) (2(k+1))=2[sum from k=1 to n (k·2~k-n·2~n)]+sum from k=1 to n 2~k∴ sum from k=1 to n (k·2~k)=n·2~(n+1)-(2~(n+1)-2) 有许多同志会感兴趣于研究sum from k=1 to n (k~p 2~k)     

p-级数(p为偶数)求和的递推公式

运用付里叶级数推导p-级数sum from n=1 to∞1/n~p(p为偶数)求和的递推公式,运用递推公式计算sum from n=1 to∞1/n~p1(p=2,4,6,8,10,12)的和.     

用■变换求解自然数方幂之和

<正> 本文采用(?)变换方法求解自然数方幂的部分和,得到了计算 S_n(m)=sum from i=1 to n i~m 的一般公式.定理1.若记 u_k=k~m,则数列{u_n}满足 m+1阶差分方程sum from k=0 to n+1(-1)~kC_(m+1)~ku_(n+m-k)=0.(1)定理2.自然数 m 次幂的部分和数列{S_n(m))满足 m+2阶差分方程sum from k=0 to m+2(-1)~kC_(m+2)~kS_(n+m+2-k)=0.(2)     

Hardy-Hilbert型不等式的一个加强

改进了Hlder不等式,并利用加强的Hlder的不等式对联系β函数的带参数的Hardy-Hilbert型不等式进行了改进,建立一个新的形如sum from n=1 to ∞ sum from m=1 to ∞(ambn/(m+n)λ)/相似文献   

关于Riemann Zeta函数的一些级数和

本文提出一种形如 sum from x=2 to ∞( ) f(x)ξ(x)的级数的求和法并能写成明显的公式。     

SOME LIMIT PROPERTIES AND THE GENERALIZED AEP THEOREM FOR NONHOMOGENEOUS MARKOV CHAINS

Let(ξ_n)_(n=0)~∞ be a Markov chain with the state space X = {1, 2, ···, b},(g_n(x, y))_(n=1)~∞ be functions defined on X × X, and F_(m_n,b_n)(ω) =1 /b_n sum from k=m_n+1 to m_n+b_n g_k(ξ_(k-1), ξ_k).In this paper the limit properties of F_(m_n,b_n)(ω) and the generalized relative entropy density f_(m_n,b_n)(ω) =-(1/b_n) log p(ξ_(m_n,m_n+b_n)) are discussed, and some theorems on a.s. convergence for(ξ_n)_n=0~∞ and the generalized Shannon-McMillan(AEP) theorem on finite nonhomogeneous Markov chains are obtained.     

Euler-Maclaurin 公式与渐近估计

若 f(x)是连续可微函数,那么我们可以用 f(x)及其导函数 f′(x)的有关积分表示有限和 sum from k=n+1 to m f(k),这就是重要的 Euler-Maclaurin 公式.令 m 趋于无穷,我们就可以用广义积分表示出相应的无穷级数.更一般地,当级数是函数项级数 sum from k=1 to ∞ f(k,t)时,这个级数可用含参数 t 的广义积分表示出来.这对于研究级数的和函数的渐近性质常常是很有用的.本文先介绍 Euler-Maclaurin 公式,然后给出它在渐近估计方面的几个例子.     

关于一道高等数学竞赛试题的探索与拓广

给出了2004年浙江省大学生高等数学竞赛一题得分率较低的压轴题(判断级数sum from n=1 to ∞ 1/n((n!)~α)～(1/n)的敛散性,其中α>0为常数)的五种不同的解法,建立了它的如下的拓广结果:当α>1且正项级数sum from i=1 to ∞ 1/(a_i~α)收敛时,级数sum from n=1 to ∞ 1/((multiply from i=1 to n)ai)α～(1/n)收敛;当0<α≤1,0相似文献   

The series sum from(n=1) to ∞(1/(n~(k 1))e(-z~(2k))/(n~(2k)))(oddk) and Riemann Zeta function

J.Tennenbaum discussed the function sum from n=1 to ∞() 1/n~2 e~(-2/n) in 1977.Zhang Nanyue discussed the function sum from n=1 to 1 () 1/n~2e~(-z~2/n~2) in 1983.Now we discuss the functions sum from n=1 to ∞ () 1/n~(k 1).e~(z~(2k)/n~(2k))(kpositive odd)in this paper which finds representations of two integrales about Riemann Zeta function     

COMPOSITION OPERATORS BETWEEN SOME WEIGHTED HARDY SPACES

Let D be the unit disc and H(D) be the set of all analytic functions on D. In [2], C. Cowen defined a space H = f ∈ H(D) : f(z) =sum from k=o to ∞ ak(z + 1)k, z∈ D, ‖f‖2 = sum from k=o to ∞ |ak|24k < ∞In this article, the authors consider the similar Hardy spaces with arbitrary weights and discuss some properties of them. Boundedness and compactness of composition operators between such spaces are also studied.     

核的分解与极大广义Bochner-Riesz平均

设l∈N,δ=k/p-k 1/2,以及相似文献   

一类组合不等式的简证与推广

利用概率方法给出了形如sum from k=1 to n(1/k)>π/4(sum from k=1 to n((-1)k-1Cnk)1/(k～1/2))与sum from k=1 to n(1/k)<2～(1/2)(sum from k=1 to n((-1)k-1Cnk)1/k2)1/2的组合不等式.     

Hilbert重级数定理的一个改进

The object of this note is to prove the followingTheorem Let{a_n}and{b_n}be sequences of real numbers such that0<∑∑a_n~2<+∞and0<∑b_n~2<+∞.Then we have the inequalitysum from m=1 to∞sum from n=1 to∞a_mb_n/m+n<{sum from n=1 to∞(π-θ/n~(1/2)a_n~2}~1/2{sum from n=1 to∞(π-θ/n~(1/2)b_n~2}~1/2 (1)whereθ=3/2~(1/2)-1=1.121320343.     

Positive solutions to m-point boundary value problem of fractional differential equation

In this paper, we study the multiplicity of positive solutions to the following m-point boundary value problem of nonlinear fractional differential equations: Dqu(t) + f(t, u(t)) = 0, 0 < t < 1, u(0) = 0, u(1) =sum (μiDpu(t)|t = ξi ) from i =1 to ∞ m-2, where q ∈R , 1 相似文献   

半线性蜕缩椭圆型方程的Dirichlet问题

设Ω(?)R~n(n≥2)是光滑有界区域.讨论如下的半线性蜕缩椭圆型方程的Dirichlet问题Lu ≡-sum from i,j=1 to n((?)/(?)x_i)(aij(x)((?)u/(?)xj)=g(x,u) (x,u),在Ω中,u=0,在(?)Ω上。(1)这里,且sum from i,j=1 to n(aijξiξj≥k sum from i=1 to n(ρ~a_i(x)ξ_i~2),(?)x∈(?),(?)ξ∈R~n,(2)     

常系数非齐线性递推式的解的显式表示

本文给出常系数非齐线性递推式(?)的解的显式表达式 H(m)=sum from i=0 to k-1(sum from j=i to k-1 b_ja_(k-j+i))D_(m-k-i)+sum from i=0 to m-k D_if(m-i)(m≥k)其中D_m=sum x_1+2x_2+…+kx_k=m x_j≥0(i=1,2,…,k)(?)a_1~x1a_2~x2…a_k~xk.     

用〔F,d_n〕平均逼近周期函数

设f(x)∈L_(2π)的Fourier级数为 f(x)～a_0/2+sum from n=1 to ∞ (a_ncosnx+b_nsinnx)sum from n=0 to ∞(A_n(f,x)) (1)以s_n(f,x)sum from i=0 to n(f,x)表示(1)第n部分和。称序列     

A NECESSARY AND SUFFICIENT CONDITION FOR THE OSCILLATION OF HIGHER-ORDER NEUTRAL EQUATIONS WITH SEVERAL DELAYS

Consider the higher-order neutral delay differential equationd~t/dt~n(x(t)+sum from i=1 to lp_ix(t-τ_i)-sum from j=1 to mr_jx(t-ρ_j))+sum from k=1 to Nq_kx(t-u_k)=0,(A)where the coefficients and the delays are nonnegative constants with n≥2 even. Then anecessary and sufficient condition for the oscillation of (A) is that the characteristicequationλ~n+λ~nsum from i=1 to lp_ie~(-λτ_i-λ~n)sum from j=1 to mr_je~(-λρ_j)+sum from k=1 to Nq_ke~(-λρ_k)=0has no real roots.     

利用等价无穷小判定级数敛散性举例

利用比较审敛法的极限形式可知,若sum from n=1 to ∞ (u_n)与sum from n=1 to ∞( v_n)都是正项级数,且n→∞ 时,u_n与v_n为等价无穷小,则sum from n=1 to ∞( u_n)与sum from n=1 to ∞( v_n)有相同敛散性.利用此结论可以不求极限,而用等价无穷小直接判定级数的敛散性.下面举例说明.     

广义调和级数的推广

将广义调和级数sum from n=1 to ∞ 1/n~x推广为一类指数项级数sum from n=1 to ∞ a_nd_n~x,并证明了这类指数项级数有结构简单的收敛域,其和函数的性质与幂级数的相似.