有趣的数字

数字一、二、三、四、五、六、七、八、九、十、个、十、百、千、万、亿不仅能用于数学中的计数,在诗歌、对联、书信、日常生活中,也有着广泛的应用,数字入联、入诗,构思精巧,用字奇特,内涵深邃,诗意盎然,别具韵味,闪烁着迷人的光芒,能起到意想不到的效果,给人以美的享受和隽永     

2005年遵义市数学中考试题分析

整套试卷注重考查了数学的基础知识,继续加强几种基本技能、基本能力的考查力度,增强了数学在实际生活中的应用性,突出了数学的探究、建模思想,注重与新课改教材的接轨,反映了数学的终结目标———应用于生活.一、试题特点1.继续保持稳定,突出考查学科知识的主干内容所考内容尽量做到全面、适度,又突出支撑学科的知识体系的主干,卷中作为初中数学最基本内容的题有1、2、3、4、5、6、7、11、12、13、14、15、16、17、19、21、22、23,约占47%.代数约占54%,几何约占46%,分配合理.方程思想、函数思想、分类思想、数形结合思想在试题中有所反映,…     

华润资金管理“特色”

提起华润,你首先想到的是华润万家、苏果、欢乐颂,还是雪花啤酒、怡宝饮料、华润食品,抑或是华润地产、电力、新能源、水泥、燃气、医药、金融,甚至是微电子、纺织、化工？粗略数算,顿觉华润的多元化真是名副其实。     

应用概率的研究领域与模型

应用概率是概率论的重要组成部分,它是研究物理、生物、经济、社会、工程、管理等实际领域中所提出的一些随机模型的数学理论的,它的抽象概念往往借助于这些领域中的术语来表达,如服务、等待、库容、首次放空、策略、效益、存货量、可靠度、寿命等等. 更具体地说,应用概率的研究范围可包括如下领域中的随机模型: 物理:统计力学,量子理论,冶金学,天文学等; 生物:生态学,遗传学,流行病学等; 社会:学习理论,经济学,人口学等; 工程与管理:排队,存储,可靠性,决策,更新,定货,风险,交通等.     

巧用统一代数替换法证明三角形不等式

众所周知,数学奥林匹克中三角形不等式证明试题屡出不穷,三角形不等式,包含三角形的各种元素(三边a、b、c,内角A、B、C及三角式,半周长s,外接圓半径R,内切圆半径r,旁切圆半径a、r_b、r_c,高h_a、h_b、h_c、中线m_a、m_b、m_c,角平分线t_a、t_b、t_c,面积s_△),可谓千姿百态,但往往有其共同特点:条件简单,结论复杂;因而证法灵活多变,颇有难度。     

三位凑“20”数巧乘同数列

三位数凑“20”数——指三个数字之和为“20”的数列,如：3、8、9,4、7、9,7、7、6,8、8、4。……等,这些数列去乘二个同数,三个或四个同数,均有一些简便的巧妙方法,这是多年经验总结,也是合乎数学原理,是把笔算、心算、珠算有机她结合起来,加也灵活运用,因此它省力、省心、省时间、快速、好忆、启迪智力,具体如下。     

《经济数学》征稿启事

正本刊是经济数学理论核心刊物,主要刊登数量经济学、数理经济学、计量经济学、经济对策论、经济控制论、经济预测与决策和经济应用数学领域中具有创造性的研究成果。一、来稿要求:1.内容充实,论点明确,论据可靠,数据准确,文字精炼。来稿一式两份,同时附中、英文的标题、摘要、关键词及中图分类号,中、英文作者名、作者所在单位的全称和单位所在的省(或直辖市、自治区)市及当地的邮政编码及作者姓名、出生年月、性别、籍贯、职称、学位、电子邮箱     

上海市崇明中学简介

上海市崇明中学,创建于1915年,2007年成为上海市实验性、示范性高级中学。学校秉承"志存高远、自强不息"的校训,以"自主教育"为办学特色,推动体、艺、科等特色项目建设,构建富有校本特色的课程体系,努力打造"理念先进、质量高位、特色鲜明"的优质品牌学校。学校全面开设基础型、拓展型、研究型三类课程,成立了文学社、金钥匙、机器人、合唱团、舞蹈团、射箭、板球等     

三角形外接圆与内切圆的性质及推广

<正>性质如图1,⊙O、⊙I分别是△ABC的外接圆和内切圆,D、E、F分别是⊙I在三边上的切点,AI、BI,CI分别交⊙O于点R、S、T,则RD、SE、TF、OI四线共点,且△RST∽△DEF.证明设RD交OI于点P_1,SE交OI于点P_2,连结OR、OS、ID、IE,     

2011年中考“课题学习”类试题例析

“课题学习”类试题在近几年各地中考试题中频频出现,2011年尤为凸出,如北京、贵阳、盐城、南京、苏州、江西等省市的试卷中都有这类考题．此类试题通常以阅读理解、探索研究、实验操作等不同形式呈现,或以恰当的数学知识为素材,或以几何图形为题材,或以数学问题为背景等,通过对相关问题的描述、观察、操作（包括数据分析、整理、运算或作图、证明）、归纳、探究等,由问题再发现问题,并创新性地解答问题．试题在注重考查相关基础知识,基本技能、方法的同时,更注重考查考生对相关知识理解、联想、探究、发现、归纳、总结及创新的能力,是近几年特别是2011年中考命题中出现的新题型、新亮点．     

High order implicit collocation method for the solution of two‐dimensional linear hyperbolic equation

In this article, we introduce a high‐order accurate method for solving the two dimensional linear hyperbolic equation. We apply a compact finite difference approximation of fourth order for discretizing spatial derivatives of linear hyperbolic equation and collocation method for the time component. The resulted method is unconditionally stable and solves the two‐dimensional linear hyperbolic equation with high accuracy. In this technique, the solution is approximated by a polynomial at each grid point that its coefficients are determined by solving a linear system of equations. Numerical results show that the compact finite difference approximation of fourth order and collocation method give a very efficient approach for solving the two dimensional linear hyperbolic equation. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009     

A hybrid collocation method for a nonlinear Volterra integral equation with weakly singular kernel

This work is concerned with the numerical solution of a nonlinear weakly singular Volterra integral equation. Owing to the singular behavior of the solution near the origin, the global convergence order of product integration and collocation methods is not optimal. In order to recover the optimal orders a hybrid collocation method is used which combines a non-polynomial approximation on the first subinterval followed by piecewise polynomial collocation on a graded mesh. Some numerical examples are presented which illustrate the theoretical results and the performance of the method. A comparison is made with the standard graded collocation method.     

High order compact solution of the one‐space‐dimensional linear hyperbolic equation

In this article, we introduce a high‐order accurate method for solving one‐space dimensional linear hyperbolic equation. We apply a compact finite difference approximation of fourth order for discretizing spatial derivative of linear hyperbolic equation and collocation method for the time component. The main property of this method additional to its high‐order accuracy due to the fourth order discretization of spatial derivative, is its unconditionally stability. In this technique the solution is approximated by a polynomial at each grid point that its coefficients are determined by solving a linear system of equations. Numerical results show that the compact finite difference approximation of fourth order and collocation method produce a very efficient method for solving the one‐space‐dimensional linear hyperbolic equation. We compare the numerical results of this paper with numerical results of (Mohanty, 3 .© 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2008     

The combination of collocation,finite difference,and multigrid methods for solution of the two‐dimensional wave equation

In this article, we apply compact finite difference approximations of orders two and four for discretizing spatial derivatives of wave equation and collocation method for the time component. The resulting method is unconditionally stable and solves the wave equation with high accuracy. The solution is approximated by a polynomial at each grid point that its coefficients are determined by solving a linear system of equations. We employ the multigrid method for solving the resulted linear system. Multigrid method is an iterative method which has grid independently convergence and solves the linear system of equations in small amount of computer time. Numerical results show that the compact finite difference approximation of fourth order, collocation and multigrid methods produce a very efficient method for solving the wave equation. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2008     

Collocation-approximation methods for nonlinear singular integrodifferential equations in Banach spaces

A new approximation method is proposed for the numerical evaluation of the nonlinear singular integrodifferential equations defined in Banach spaces. The collocation approximation method is therefore applied to the numerical solution of such type of nonlinear equations, by using a system of Chebyshev functions.Through the application of the collocation method is investigated the existence of solutions of the system of non-linear equations used for the approximation of the nonlinear singular integrodifferential equations, which are defined in a complete normed space, i.e., a Banach space.     

A numerical method to solve a class of linear integro‐differential equations with weakly singular kernel

In this paper, a collocation method based on the Bessel polynomials is introduced for the approximate solution of a class of linear integro‐differential equations with weakly singular kernel under the mixed conditions. The exact solution can be obtained if the exact solution is polynomial. In other cases, increasing number of nodes, a good approximation can be obtained with applicable errors. In addition, the method is presented with error and stability analysis. Copyright © 2012 John Wiley & Sons, Ltd.     

The solution of linear and nonlinear systems of Volterra functional equations using Adomian–Pade technique

The purpose of this study is to implement Adomian–Pade (Modified Adomian–Pade) technique, which is a combination of Adomian decomposition method (Modified Adomian decomposition method) and Pade approximation, for solving linear and nonlinear systems of Volterra functional equations. The results obtained by using Adomian–Pade (Modified Adomian–Pade) technique, are compared to those obtained by using Adomian decomposition method (Modified Adomian decomposition method) alone. The numerical results, demonstrate that ADM–PADE (MADM–PADE) technique, gives the approximate solution with faster convergence rate and higher accuracy than using the standard ADM (MADM).     

A Generalization of the Arnold-Wendland Lemma to a Modified Collocation Method for Boundary Integral Equations in ℝ3

We prove quasioptimal and optimal order estimates in various Sobolev norms for the approximation of linear strongly elliptic periodic pseudodifferential equations in two independent variables by a modified method of nodal collocation by odd degree polynomial splines. In the one-dimensional case, our method coincides with the method of nodal collocation when odd degree polynomial splines are employed for the trial functions. The convergence analysis is based on an equivalence which we establish between our method and a nonstandard Galerkin method for an operator closely related to the given operator. This equivalence is realized through a crucial intermediate result (which we now term the Arnold-Wendland lemma) to connect the solution of central finite difference equations and that of certain nonstandard Galerkin equations. The results of this paper are genuine two-dimensional generalizations of the results obtained by ARNOLD and WENDLAND in [2] for the one-dimensional equations.     

Adjoint Error Estimation for a Pseudo-Spectral Approach to Stochastic Field-Circuit Coupled Problems

This work is concerned with the numerical approximation of random differential-algebraic equations (DAE), arising from electric field-circuit coupled problems. Using the adjoint DAE, the stochastic collation error is analyzed. The error can be evaluated using a collocation method of the same polynomial degree for the adjoint DAE. In particular, there is no need for constructing a solution of higher polynomial degree. The accuracy of the estimator is illustrated by a numerical example. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

非线性积分方程迭代配置法的渐近展开及其外推

非线性积分方程迭代配置法的渐近展开及其外推韩国强（华南理工大学计算机工程与科学系）ＡＳＹＭＰＴＯＴＩＣＥＲＲＯＲＥＸＭＮＳＩＯＮＳＡＮＤＥＸＴＲＡＰＯＬＡＴＩＯＮＦＯＲＴＨＥＩＴＥＲＡＴＥＤＣＯＬＬＯＣＡＴＩＯＮＭＥＴＨＯＤＳＯＦＮＯＮＬＩＮＥＡＲＩ...