导数在研究函数单调性中的应用

函数的单凋性是函数的重要性质，若利用定义求解，变形的技巧和方法是阻碍问题解决的难点，而利用导数研究单调性问题，可有效地突破这个难点，利用导数的相关知识来研究函数的单调性已成为高考的热点．     

比较对数大小的一般方法

比较对数大小的一般方法杜家栋（四川省三台师范学校６２１１００）比较两个相差甚微且底数和真数均不相同的对数的大小，由于常用的比较法、中间值法都难以奏效，因此历来是高中数学教学的难点．近十年来，不少论文如［１］、［２］等对此进行了有益的探讨，给出的一些结...     

结合高考试题谈二面角及其平面角

二面角及其平面角是立体几何教学中的重点和难点．在立体几何中，两平面的位置关系主要是用它们所成的二面角来刻画的，而将二面角这个空间图形数量化，采用的是构造二面角的平面角的手法，使问题转化为平面几何问题来研究．二面角的平面角所在平面与二面角的棱垂直（线面...     

直线和圆的方程

1本单元重、难点及方法指导 1）本单元重点知识： 通过本单元的学习，需要重点掌握以下知识：直线的倾斜角和斜率的概念以及它们之间的关系；直线方程的五种形式；两条直线位置关系的判定方法；两条直线所成角与点到直线距离的计算方法；用简单线性规划的办法求一些函数的最值；曲线和方程的概念及轨迹方程的求取方法；圆的标准方程和一般方程；从代数和几何两个不同角度来判断直线和圆以及圆与圆的位置关系；研究圆的切线和弦长问题的一般方法．     

又一种比较对数大小的方法——函数单调法

又一种比较对数大小的方法———函数单调法甘大旺（武汉东西湖吴家山中学４３００４０）比较两个相差甚微且真数与底数均不相等的对数的大小，确实是高中数学教学的难点之一．文［１］、［２］分别探索了突破这一难点的不同方法，耐人寻味．本文再介绍一种方法———函数...     

浅析教学难点的形成因素及其对策

浅析教学难点的形成因素及其对策２２５５００江苏省姜堰市第二中学石志群常听某些教师讲：＂学生听不懂的就是难点．＂尽管有点道理，却很不科学．比如，对＂难点＂的看法就有失偏废．教学难点尽管教来困难，但并非无能为力．只要深入分析＂难＂的原因所在，运用恰当的教...     

判断三角形解的个数

已知三角形的两边和其中一边的对角判断三角形的解的个数问题是同学们学习的一个难点，教材利用数形结合的方法总结得出两解、一解、无解的方法，但由于此法情形复杂，同学往往不易掌握．经研究发现一简捷有效方法如下：     

美式期权自由边界的计算方法

美式期权的自由边界问题在金融工程文献中已经引起了广泛的关注,然而,它的数值计算方法一直是一个难点.基于差分技巧,给出了满足具有有限到期日的美式期权自由边界的两种计算方法,即,根据股票期权价格和相应的偏导数来确定自由边界条件.数值结果表明了上述两种方法下自由边界是一致性的.此外研究结果对自由边界的计算提供很好的科学依据.     

构造异面直线所成角的方法

异面直线所成角是中学数学中的重点与难点,本文旨在和同学们一起探索解这类问题的思路、方法和规律.一、平移一线来构造异面直线所成角异面直线所成角一般是在几何体中给出的,往往是以线段的形式出现,作两条异面直     

排列、组合与二次式定理

2 重点、难点、热点分析。分类计数原理与分步计数原理是本单元的重点．分类计数和分步计数都是涉及完成一件事的不同方法的种数，它们的区别在于：分类计数原理是办事方法分为若干类，各类中各种方法相互独立，并且任一类中任一种方法都可以单独完成这件事；分步计数原理是办事分为若干步进行，各个步骤相互依存，各步中任一种方法都只完成一个步骤，必须各个步骤都完成了，这件事才算完成．因此，分辨清楚办事方法是分类还是分步，是正确使用两个原理的前提，也是本单元的难点所在．     

供应商综合实力的指标评价体系及模糊判断

供应链管理(SCM)是在IT技术广泛应用的基础上产生的一种先进、新颖的管理哲理与方法.在供应链(SC)中,合理地评价供应商的综合实力是优化选择具有敏捷性和相容性合作伙伴的关键,也对提高整个SC的竞争力有着极其重要的作用.构建了供应商综合实力的指标评价体系及评价因素集、权重集,提出一个通用的模糊判断模型及相应的算法,并利用该算法较好地解决了对供应商综合实力进行定量判断的问题.     

Large sources and closure operators in topological constructs

This paper is a contribution to the question: How to use categorical methods in the case of non-cowellpoweredness? We will focus on classes of morphisms/conglomerates of sources usually appearing as parts of a factorization structure.     

The Freedom to Extend OpenMath and its Utility

OpenMath is a standard for representing the semantics of mathematical objects. It differs from Presentation MathML in not being directly concerned with the presentation of the object, and from Content MathML 2 in being extensible. How should these extensions be performed so as to maximize the utility (which includes presentation) of OpenMath? How could publishers have the freedom to extend and let consumers find their way with expressions discovered on the Web? The answer up to now has been, too often, to say “this is not specified” whereas the existing content dictionary mechanism of OpenMath allows it to include formal properties which state mathematical facts that should stay uncontradicted while manipulating the symbols. The contribution of this paper is to propose methods to exploit the content dictionaries so as to allow an OpenMath-consuming tool to process expressions even if containing symbols it did not know about before. This approach is generalized to allow such newly discovered symbol to be, for example, rendered or input.      

Symmetric collocation methods for linear differential-algebraic boundary value problems

Summary. We present symmetric collocation methods for linear differential-algebraic boundary value problems without restrictions on the index or the structure of the differential-algebraic equation. In particular, we do not require a separation into differential and algebraic solution components. Instead, we use the splitting into differential and algebraic equations (which arises naturally by index reduction techniques) and apply Gau?-type (for the differential part) and Lobatto-type (for the algebraic part) collocation schemes to obtain a symmetric method which guarantees consistent approximations at the mesh points. Under standard assumptions, we show solvability and stability of the discrete problem and determine its order of convergence. Moreover, we show superconvergence when using the combination of Gau? and Lobatto schemes and discuss the application of interpolation to reduce the number of function evaluations. Finally, we present some numerical comparisons to show the reliability and efficiency of the new methods. Received September 22, 2000 / Revised version received February 7, 2001 / Published online August 17, 2001     

Development and Implementation of an Integrated Mathematics/Science Preservice Elementary Methods Course

If integration of mathematics and science is to occur, teacher preparation programs at colleges and universities must provide leadership in developing and modeling methods of teaching integrated content. This paper describes the development and implementation of an integrated mathematics/science preservice elementary methods course at the University of Connecticut. In planning the course several questions were addressed: (a) What does integration of mathematics and science mean? (b) What content should be taught in an integrated mathematics/science (IM/S) elementary methods course? and (c) How should an IM/S elementary methods course be taught? An important element of the course involved enlisting an exemplary elementary teacher who was released from her classroom one day per week to co-teach the methods class. Establishing a definition of integration proved to be one of the most challenging aspects of course development. The authors determined that most difficulties in integration of disciplines result from attempts to “force” the integration. As the team struggled with the philosophical, theoretical and logistical problems in the development of the course, it became apparent why integration has not been more widely implemented. It is believed this model can be adapted to allow for integration of all content areas. Plans are currently underway to incorporate social studies into the methods class for Fall of 1993.     

水凝胶类软物质材料理论中的数学问题

 水凝胶是一种具有广泛应用前景的软物质材料,一直是材料学家、物理化学家们关心的热点,目前有很多实验和专利产品.其机理和模型的研究处于初期阶段,本文综述该领域的部分进展,包括形变、微结构和宏观性质等的数学模型和相关计算方法,一并列出一些亟待解决的问题.     

数学建模课内容和教学方法的探讨

拟就以下内容进行了探讨 .(i)该课程究竟应该讲什么内容、怎样讲 ,才能使学生在较短的时间内 ,掌握数学建模的基本知识和基本方法 ;(ii)该课程怎样与数学实验更好地结合起来 ,以培养学生的动手能力 ;(iii)该课程应采用什么样的教学手段和教学方法 ,才能加大课堂信息量 ,加强直观性和趣味性等 .我们的解决方法是 :(i)以介绍建立数学模型为主 ,按数学知识内容的不同来选取数学模型的典型案例 ,通过案例介绍 ,使学生学会怎样建立模型 .(ii)适当介绍数学软件包 ,让学生掌握运用软件包来求解模型能力 .(iii)做大作业 ,教员给出题目 ,学生自己收集资料、讨论、上机求解 ,最后写出报告 .(iv)开展多媒体教学 ,对主要的教学内容进行模块化教学 ,将建模分成 1 4个专题 ,做成 1 4个多媒体课件     

Cluster synchronization for directed community networks via pinning partial schemes

In this paper, we focus on driving a class of directed networks to achieve cluster synchronization by pinning schemes. The desired cluster synchronization states are no longer decoupled orbits but a set of un-decoupled trajectories. Each community is considered as a whole and the synchronization criteria are derived based on the information of communities. Several pinning schemes including feedback control and adaptive strategy are proposed to select controlled communities by analyzing the information of each community such as indegrees and outdegrees. In all, this paper answers several challenging problems in pinning control of directed community networks: (1) What communities should be chosen as controlled candidates? (2) How many communities are needed to be controlled? (3) How large should the control gains be used in a given community network to achieve cluster synchronization? Finally, an example with numerical simulations is given to demonstrate the effectiveness of the theoretical results.     

A family of three-point methods of optimal order for solving nonlinear equations

A family of three-point iterative methods for solving nonlinear equations is constructed using a suitable parametric function and two arbitrary real parameters. It is proved that these methods have the convergence order eight requiring only four function evaluations per iteration. In this way it is demonstrated that the proposed class of methods supports the Kung-Traub hypothesis (1974) [3] on the upper bound 2ⁿ of the order of multipoint methods based on n+1 function evaluations. Consequently, this class of root solvers possesses very high computational efficiency. Numerical examples are included to demonstrate exceptional convergence speed with only few function evaluations.     

Lag synchronization of complex networks via pinning control

This paper mainly investigates the lag synchronization of complex networks via pinning control. Without assuming the symmetry and irreducibility of the coupling matrix, sufficient conditions of lag synchronization are obtained by adding controllers to a part of nodes. Particularly, the following two questions are solved: (1) How many controllers are needed to pin a coupled complex network to a homogeneous solution? (2) How should we distribute these controllers? Finally, a simple example is provided to demonstrate the effectiveness of the theory.