Mathematisches Denken in der Linearen Algebra

How can first years students learn to think and act mathematically by learning Linear Algebra? We want to present an approach that considers reflection of mathematical acting and its connections to general thinking to be an important part of learning. By understanding mathematics as a specific conventionalization of general thinking, patterns of general thinking can become the starting point for learning mathematics. This points out the specific contribution that mathematics can give to describe reality. By example of Linear Algebra, we discuss the common ground and differences between thinking in mathematics and in non-mathematical subjects. Based on this discussion, we analyse why and how these reflections can be objects of learning.     

A few pedagogical designs in linear algebra with Cabri and Maple

Since the 90’s, with the creation of new electronic environments for learning and teaching, several research groups in Mathematics Education have been emerging and developing. This article elaborates few pedagogical designs in Linear Algebra supported by both the geometrical micro-world Cabri and the computer algebra system Maple. Stumbling blocks in the learning of Linear Algebra are examined, more exactly linear transformations, eigenvectors, quadratic forms, conics with changes of bases and finally singular values. Encountering a special group of students very eager to explore the world of linear algebra, we initiated a classification of linear transformations of the Euclidean plane R² via ellipses.     

Motivating the concept of eigenvectors via cryptography

New methods of teaching linear algebra in the undergraduatecurriculum have attracted much interest lately. Most of thiswork is focused on evaluating and discussing the integrationof special computer software into the Linear Algebra curriculum.In this article, I discuss my approach on introducing the conceptof eigenvectors and eigenvalues, which I have used for the last3 years in my Linear Algebra course. I offer some examples onhow I have attracted the interest of our students via Hill ciphering,a method of cryptography. After emphasizing the effect of alinear transformation in a vector space and the importance ofeigenvectors, I show how students’ motivation and understandingtowards one of the abstract concepts in Linear Algebra; eigenvaluesand eigenvectors have grown positively.     

《线性代数》内容的关联性研究

《线性代数》学科知识点关联性强、相互交叉相互引证的情况比较多.清晰把握知识点之间的关系成为有效教学的重要前提.本文通过建构知识点关联层次图,试图理顺知识点关系、把握好内容格局,并结合教学经验提出一种教学时序.     

逆矩阵的判定及计算方法

线性代数是大学教育中一门难度较高的基础必修课程,而逆矩阵是教学过程中一个主要概念,对研究其他线性结构有着非常重要的作用.本文通过对逆矩阵定义的分析,汇总若干个判定矩阵是否可逆的方法,同时提供了多种逆矩阵的计算技巧,包括利用计算机技术简化繁琐的计算过程,这些都是学习者在学习过程中需要掌握的重要内容.本文旨在协助教师在开展教学时,能够举一反三,以点带面来引导学生将所学知识融合,注重知识点之间的相关性学习;同时,也帮助学习者能够更加全面的认识逆矩阵这一重要概念.     

线性代数教学中的归纳与演绎方法

针对线性代数概念多、内容抽象、逻辑性强等特点，介绍归纳和演绎方法在线性代数教学中的应用，并借助具体案例加以说明．     

The effect of project-based learning on students’ statistical literacy levels for data representation

The point of this study is to define the effect of project-based learning approach on 8th Grade secondary-school students’ statistical literacy levels for data representation. To achieve this goal, a test which consists of 12 open-ended questions in accordance with the views of experts was developed. Seventy 8th grade secondary-school students, 35 in the experimental group and 35 in the control group, took this test twice, one before the application and one after the application. All the raw scores were turned into linear points by using the Winsteps 3.72 modelling program that makes the Rasch analysis and t-tests, and an ANCOVA analysis was carried out with the linear points. Depending on the findings, it was concluded that the project-based learning approach increases students’ level of statistical literacy for data representation. Students’ levels of statistical literacy before and after the application were shown through the obtained person-item maps.     

The convergence of the modified Gauss–Seidel methods for consistent linear systems

In this paper we present a convergence analysis for the modified Gauss–Seidel methods given in Gunawardena et al. (Linear Algebra Appl. 154–156 (1991) 125) and Kohno et al. (Linear Algebra Appl. 267 (1997) 113) for consistent linear systems. We prove that the modified Gauss–Seidel method converges for some values of the parameters in the preconditioned matrix.     

Student performance and attitudes in a collaborative and flipped linear algebra course

Flipped learning is gaining traction in K-12 for enhancing students’ problem-solving skills at an early age; however, there is relatively little large-scale research showing its effectiveness in promoting better learning outcomes in higher education, especially in mathematics classes. In this study, we examined the data compiled from both quantitative and qualitative measures such as item scores on a common final and attitude survey results between a flipped and a traditional Introductory Linear Algebra class taught by two individual instructors at a state university in California in Fall 2013. Students in the flipped class were asked to watch short video lectures made by the instructor and complete a short online quiz prior to each class attendance. The class time was completely devoted to problem solving in group settings where students were prompted to communicate their reasoning with proper mathematical terms and structured sentences verbally and in writing. Examination of the quality and depth of student responses from the common final exam showed that students in the flipped class produced more comprehensive and well-explained responses to the questions that required reasoning, creating examples, and more complex use of mathematical objects. Furthermore, students in the flipped class performed superiorly in the overall comprehension of the content with a 21% increase in the median final exam score. Overall, students felt more confident about their ability to learn mathematics independently, showed better retention of materials over time, and enjoyed the flipped experience.     

Specht's ratio and complementary inequalities to Golden–Thompson type inequalities on the Hadamard product

As a converse of the arithmetic–geometric mean inequality, W. Specht [Math. Z. 74 (1960) 91–98] estimated the ratio of the arithmetic mean to the geometric one. In this paper, we shall show complementary inequalities to the matricial generalization of Oppenheim's inequality and the Golden–Thompson type inequalities on the Hadamard product by T. Ando [Linear Algebra Appl. 26 (1979) 203; Linear Algebra Appl. 241–243 (1996) 105], in which Specht's ratio plays an important role. As an application, we shall obtain a complementary inequality to the Hadamard determinant inequality.     

A support learning programme for first-year mathematics*

ABSTRACT

This article is a follow-up to an earlier paper on the mathematics support learning tutorial programme (SLT), an intervention programme at The University of Queensland that targets students considered to be at risk of failing Calculus and Linear Algebra I, the first tertiary level mathematics subject at The University of Queensland. The first paper (Hillock, P., Jennings, M., Roberts, A., & Scharaschkin, V. (2013). Amathematics support programme for first-year engineering students. International Journal of Mathematical Education in Science and Technology, 44(7), 1030–1044) reported on the inaugural programme implemented in 2012. This article provides an update of the progress of the SLT since 2012. We provide statistics for the subsequent 12 semesters to Semester 2, 2018 and describe the evolution of the SLT since its implementation. Statistical analysis of the additional data and student feedback indicate that the SLT continues to have a positive impact on student learning, with weak students making significant gains from attending the programme.     

On some determinantal identities formation laws

We show that Muir’s law of extensible minors, Cayley’s law of complementaries and Jacobi’s identity for minors of the adjugate [Determinantal identities Linear Algebra and its Applications 52/53 (1983) pp. 769–791] are equivalent. We also show our generalization of Mühlbach/Muir’s extension principle [A generalization of Mühlbach’s extension principle for determinantal identities. Linear and Multilinear Algebra 61 (10) (2013) pp. 1363–1376] is equivalent to its previous form derived by Mühlbach. As a corollary, we show that Mühlbach–Gasca–(Lopez-Carmona)–Ramirez identity [A generalization of Sylvester’s identity on determinants and some applications. Linear Algebra and its Applications 66 (1985) pp. 221–234/On extending determinantal identities. Linear Algebra and its Applications 132 (1990) pp. 145–162] is equivalent to its generalization found by Beckermann and Mühlbach [A general determinantal identity of Sylvester type and some applications. Linear Algebra and its Applications 197,198 (1994) pp. 93–112].     

A note on k-generalized projections

In this note, we investigate characterizations for k-generalized projections (i.e., A^k = A^*) on Hilbert spaces. The obtained results generalize those for generalized projections on Hilbert spaces in [Hong-Ke Du, Yuan Li, The spectral characterization of generalized projections, Linear Algebra Appl. 400 (2005) 313–318] and those for matrices in [J. Benítez, N. Thome, Characterizations and linear combinations of k-generalized projectors, Linear Algebra Appl. 410 (2005) 150–159].     

Jordan标准形定理的初等变换证明

本文对 Jordan标准形定理给出了一种使用初等变换的证明 ,直观意义明显、易于理解 ,可用于线性代数教学 .     

The finite-to-finite strand of a learning progression for the concept of function: A research synthesis and cognitive analysis

In this paper we report validation efforts around the finite-to-finite strand of a provisional learning progression (LP) for the concept of function. We regard an LP as an empirically-verified account of how student understandings form over time and in response to instruction. The finite-to-finite strand of the LP was informed by literature on students’ thinking and learning related to functions as well as the Algebra Project’s curricular approach, which is designed for students who are traditionally underserved by mathematics education. Developing and validating an LP is a multi-step, cyclic process. Here we report on one step in this process, an item and response analysis. Data sources include 680 students’ responses to 13 multipart computer-delivered tasks. Results suggest that revisions to the items, associated scoring rubrics, and in some instances the LP are warranted. We illustrate this task, rubric, and LP revision process through an item analysis for a selected task.     

A note on extrema of linear combinations of elementary symmetric functions

This note provides a new approach to a result of Foregger [T.H. Foregger, On the relative extrema of a linear combination of elementary symmetric functions, Linear Multilinear Algebra 20 (1987) pp. 377–385] and related earlier results by Keilson [J. Keilson, A theorem on optimum allocation for a class of symmetric multilinear return functions, J. Math. Anal. Appl. 15 (1966), pp. 269–272] and Eberlein [P.J. Eberlein, Remarks on the van der Waerden conjecture, II, Linear Algebra Appl. 2 (1969), pp. 311–320]. Using quite different techniques, we prove a more general result from which the others follow easily. Finally, we argue that the proof in [Foregger, 1987] is flawed.     

High school students’ understanding of the function concept

This paper is a study of part of the Algebra Project's program for underrepresented high school students from the lowest quartile of academic achievement, social and economic status. The study focuses on students’ learning the concept of function. The curriculum and pedagogy are part of an innovative, experimental approach designed and implemented by the Algebra Project. The instructional treatment took place over 7 weeks during the Junior Year of 15 students from our target population. Immediately after instruction, a written instrument was administered followed, several weeks later, by in-depth interviews. The results are that many of our participants achieved a level of knowledge and understanding of functions on a par with beginning college students, including preservice teachers, as reported in the literature. Many conceptual difficulties that have been reported in the research literature were not as prevalent for our participants and some of them were capable of solving difficult problems involving composition of functions. We conclude that, with appropriate pedagogy, it is possible for students in the Algebra Project's target population to learn substantial and non-trivial mathematics at the high school level, and that the Algebra Project approach is one example of such a pedagogy.     

Proof of a conjecture of Fiedler and Markham

Let A be an n×n nonsingular M-matrix. For the Hadamard product AA⁻¹, M. Fiedler and T.L. Markham conjectured in [Linear Algebra Appl. 10l (1988) 1] that q(AA⁻¹)2/n, where q(AA⁻¹) is the smallest eigenvalue (in modulus) of AA⁻¹. We considered this conjecture in [Linear Algebra Appl. 288 (1999) 259] having observed an incorrect proof in [Linear Algebra Appl. 144 (1991) 171] and obtained that q(AA⁻¹)(2/n)(n−1)/n. The present paper gives a proof for this conjecture.     

Branching Numbers for Euclidean Projections onto Convex Polyhedra

The purpose of this note is to give a short proof of the theorem of Ralph in Linear Algebra Appl. 178 (1993), 249–260, on the geometry of projection maps. This theorem implies that the so-called normal maps derived from projections satisfy a general geometric criterion for bijectivity of piecewise affine maps given by Kuhn and Löwen in Linear Algebra Appl. 96 (Section 5.3), (1987), 109–129. As a consequence, one obtains Robinson's characterization of bijectivity of normal maps.