平面向量中的典型错例剖析

平面向量是高中数学必修部分的重要内容,也是高考考查的重点之一．该模块知识在数学、物理等学科中有着广泛的应用,而且考试中经常与其它数学知识进行交汇出题,综合性强．同学们在复习时,由于受知识片面性的制约,再加上方法选择不当、思考不严谨等不利因素的影响,会出现不少的解题误区．本文通过举例,对平面向量中的典型错例进行剖析,供大家学习时参考．     

高中学生数学思维障碍的成因及突破

所谓高中学生数学思维,是指学生在对高中数学感性认识的基础上,运用比较、分析、综合、归纳、演绎等思维的基本方法,理解并掌握高中数学内容而且能对具体的数学问题进行推论与判断,从而获得对高中数学知识本质和规律的认识能力．高中数学的数学思维虽然并非总等于解题,     

深刻反思 思维优化

在初中数学教学中,由于学生的年龄特征及数学认识结构水平的限制,加上非认识因素的影响反考试、升学的压力,学生在数学学习中往往对基础知识不求甚解,对基础训练不感兴趣,热衷于大量做题,不会对自己的解题方法、解题思路进行反思,不注重分析、评价和判断自己的思考方法的优劣,更不善于找出和纠正自己的错误．结果是学生模仿能力变强了,解题速度变快了,而思维水平没有根本性的提高,思维品质没有实质性的改变．因此,在平时的教学中,必须强化正确的解题思想教育．学生解完题后,教师应当给学生足够的时间进行检查、反思,回顾解题过程中所涉及的基础知识、基本技能、基本的数学思想,解决问题的思维过程,揭示问题的本质．使学生养成反思习惯,提升数学素养,完善的思维品质．     

数学教学应让学生领悟数学思想——以“数学归纳法”教学设计为例

一、问题提出 由于应试教育的影响,许多教师的教学以解题为中心,新授课的教学匆匆而过,转而进行习题训练,企图通过解题来理解知识、掌握知识、提升能力.而对概念的提出过程、概括提炼过程,公式、定理、法则的形成过程,解题思路的发现过程,解题方法的总结提炼过程等重要知识的来源匆匆带过.其结果是学生通过模仿可能会解一些简单、基础的题,但由于缺乏对数学思维过程的理解、数学思想方法的领悟、数学本质的揭示,因而学习兴趣不浓,数学思维能力不强.长此以往,数学思维能力就得不到提升.数学教学应如何展示思维过程,让学生领悟数学思想,揭示数学本质?笔者通过“数学归纳法”这节课的教学设计进行讨论.     

从技击走向审美:中国武术套路特征分析

解题是学好数学基础知识、培养和提高思维能力的重要手段,中学生思维的片面性与表面性影响他们对数学对象理解的真度和深度,通过解题错误可见一斑．研究表明,错误是把新方法与已有知识统一起来的尝试的必然结果,因此,辨认出学生知识联系上的特殊缺陷从而进行针对性引导是研究错解教学的根本目的．有限的考试时间使学生的思维高度紧张,虽然会造成较多失误,但从认知心理学的角度考虑,这种低反应时状态更利于反映考生知识技能的掌握情况和思维倾向,笔者以江苏高三高考模拟题（理）为例加以说明．     

隐含条件“隐”在何处

学生答错题的原因多种多样,有知识掌握不牢固、论证不严密、解题方法选择不当等．此外,也有心理因素和偶然因素．知识性错误是指对试题涉及到的有关知识不能正确理解,或运用不当,因此不能正确陈述解题过程和结论而导致的错误．学生在解题时,注意力集中在某些条件而经常忽视题目的隐含条件导致解题错误,这是知识性错误中常见的一种．那么隐含条件究竟“隐”在哪里？     

2006年高考湖北卷20题的探究

2006年高考湖北卷第20题形式上是一道纯解析几何题．但它确是一道独具匠心的佳题．一方面，它以解析几何中的椭圆为载体，考查对知识、方法的理饵和应用，只要能准确把握知识的本质，就能选用恰当的数学工具，得到简捷的解题方案；另一方面，让学生在自主探索中认识和理解解析几何与向量方法的本质，引导学生用探究问题的方式学习数学，跳出题海，减轻学生负担，确实具有导向作用．     

解题教学中不同解法间的过渡及内涵发掘

<正>对于一个数学题目,往往会有多种解答方法.教师在解题教学过程中,很容易出现一个误区:教师通常只是讲解了多种方法,而这些解法之间的联系以及缘由却很少触及.从而导致了课堂上学生对各种解法叹为观止,但课后并不能举一反三.学生对为什么能这样解以及还可以怎样解没有理解到本质.这是不利于数学解题教学的.本文以一道高考题的六种解法为例,探讨在解题教学中如何从一种解法过渡到另一种解法,并给出如何从题目本身出发,得到新结论与新知识的过程.     

一题多变 开阔视野

“问题是数学的心脏”．数学教学都离不开解题．因此,在数学教学过程中,运用不同的知识与方法,变换题目的形式,让学生在解题过程中发展智力,提高解题能力,这样既可使学生学得生动活泼,又可减轻学生负担,开阔视野,这也正是素质教育所要求的．数学问题的一题多变能提高学生综合分析和解决问题的能力,更能激发学生学习数学的兴趣,增强求知欲．下面是三角函数的一堂习题课,通过教师启发和指导,学生积极参与,共同讨论,融本章知识于一题多变之中,取得了较好的复习效果．题目　已知ｃｏｓα＋ｃｏｓβ＝２４ｓｉｎα＋ｓｉｎβ＝２…     

高三阶段师生解题思维差异与教学对策

课堂教学是师生共同活动的过程，其目的是使学生获取知识提高能力，落脚点在于学生．特别是学生进入高三数学复习之前，已对数学的概念、解题的规律与方法有了一定的认识，但他们对概念与概念、规律与规律、方法与方法之间的联系没有深化，缺乏对高中数学知识、整体结构的理解，知识、方法与能力等观点不高．然而他们的思维活跃、感悟快、创新能力强，数、理、化知识互相渗透力强等思维优势。     

Linear birth and death models and associated Laguerre and Meixner polynomials

We study birth and death processes with linear rates λ_n = n + α + c + 1, μ_{n + 1} = n + c, n 0 and μ₀ is either zero or c. The spectral measures of both processes are found using generating functions and the integral transforms of Laplace and Stieltjes. The corresponding orthogonal polynomials generalize Laguerre polynomials and the choice μ₀ = c generates the associated Laguerre polynomials of Askey and Wimp. We investigate the orthogonal polynomials in both cases and give alternate proofs of some of the results of Askey and Wimp on the associated Laguerre polynomials. We also identify the spectra of the associated Charlier and Meixner polynomials as zeros of certain transcendental equations.     

Affine-inscribed and affine-circumscribed polygons and polytopes

Five theorems on polygons and polytopes inscribed in (or circumscribed about) a convex compact set in the plane or space are proved by topological methods. In particular, it is proved that for every interior point O of a convex compact set in ℝ³, there exists a two-dimensional section through O circumscribed about an affine image of a regular octagon. It is also proved that every compact convex set in ℝ³ (except the cases listed below) is circumscribed about an affine image of a cube-octahedron (the convex hull of the midpoints of the edges of a cube). Possible exceptions are provided by the bodies containing a parallelogram P and contained in a cylinder with directrix P. Bibliography: 29 titles. Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 231, 1995, pp. 286–298. Translated by B. M. Bekker.     

Partitions and pairwise sums and products

A seven cell partition of N is constructed with the property that no infinite set has all of its pairwise sums and products in any one cell. A related Ramsey Theory question is shown to have different answers for two and three cell partitions.     

Distributive and Multiplication Modules and Rings

We study rings in which every ideal is a finitely generated multiplication right ideal.     

Beliefs and beyond: affect and the teaching and learning of mathematics

The importance of beliefs for the teaching and learning of mathematics is widely recognized among mathematics educators. In this special issue, we explicitly address what we call “beliefs and beyond” to indicate the larger field surrounding beliefs in mathematics education. This is done to broaden the discussion to related concepts (which may not originate in mathematics education) and to consider the interconnectedness of concepts. In particular, we present some new developments at the conceptual level, address different approaches to investigate beliefs, highlight the role of student beliefs in problem-solving activities, and discuss teacher beliefs and their significance for professional development. One specific intention is to consider expertise from colleagues in the fields of educational research and psychology, side by side with perspectives provided by researchers from mathematics education.     

Ritz and harmonic Ritz values and the convergence of FOM and GMRES

The Ritz and harmonic Ritz values are approximate eigenvalues, which can be computed cheaply within the FOM and GMRES Krylov subspace iterative methods for solving non‐symmetric linear systems. They are also the zeros of the residual polynomials of FOM and GMRES, respectively. In this paper we show that the Walker–Zhou interpretation of GMRES enables us to formulate the relation between the harmonic Ritz values and GMRES in the same way as the relation between the Ritz values and FOM. We present an upper bound for the norm of the difference between the matrices from which the Ritz and harmonic Ritz values are computed. The differences between the Ritz and harmonic Ritz values enable us to describe the breakdown of FOM and stagnation of GMRES. Copyright © 1999 John Wiley & Sons, Ltd.