Quantity and Mathematics
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Variables in Mathematics Education
Variables in Mathematics Education Susanna S. Epp DePaul University, Department of Mathematical Sciences, Chicago, IL 60614, USA http://www.springer.com/lncs Abstract. This paper suggests that consistently referring to variables as placeholders is an effective countermeasure for addressing a number of the difficulties students’ encounter in learning mathematics. The sug- gestion is supported by examples discussing ways in which variables are used to express unknown quantities, define functions and express other universal statements, and serve as generic elements in mathematical dis- course. In addition, making greater use of the term “dummy variable” and phrasing statements both with and without variables may help stu- dents avoid mistakes that result from misinterpreting the scope of a bound variable. Keywords: variable, bound variable, mathematics education, placeholder. 1 Introduction Variables are of critical importance in mathematics. For instance, Felix Klein wrote in 1908 that “one may well declare that real mathematics begins with operations with letters,”[3] and Alfred Tarski wrote in 1941 that “the invention of variables constitutes a turning point in the history of mathematics.”[5] In 1911, A. N. Whitehead expressly linked the concepts of variables and quantification to their expressions in informal English when he wrote: “The ideas of ‘any’ and ‘some’ are introduced to algebra by the use of letters. it was not till within the last few years that it has been realized how fundamental any and some are to the very nature of mathematics.”[6] There is a question, however, about how to describe the use of variables in mathematics instruction and even what word to use for them. -
Kind of Quantity’
NIST Technical Note 2034 Defning ‘kind of quantity’ David Flater This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2034 NIST Technical Note 2034 Defning ‘kind of quantity’ David Flater Software and Systems Division Information Technology Laboratory This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2034 February 2019 U.S. Department of Commerce Wilbur L. Ross, Jr., Secretary National Institute of Standards and Technology Walter Copan, NIST Director and Undersecretary of Commerce for Standards and Technology Certain commercial entities, equipment, or materials may be identifed in this document in order to describe an experimental procedure or concept adequately. Such identifcation is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the entities, materials, or equipment are necessarily the best available for the purpose. National Institute of Standards and Technology Technical Note 2034 Natl. Inst. Stand. Technol. Tech. Note 2034, 7 pages (February 2019) CODEN: NTNOEF This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2034 NIST Technical Note 2034 1 Defning ‘kind of quantity’ David Flater 2019-02-06 This publication is available free of charge from: https://doi.org/10.6028/NIST.TN.2034 Abstract The defnition of ‘kind of quantity’ given in the International Vocabulary of Metrology (VIM), 3rd edition, does not cover the historical meaning of the term as it is most commonly used in metrology. Most of its historical meaning has been merged into ‘quantity,’ which is polysemic across two layers of abstraction. -
Aquinas on Attributes
CORE Metadata, citation and similar papers at core.ac.uk Provided by MedievaleCommons@Cornell Philosophy and Theology 11 (2003), 1–41. Printed in the United States of America. Copyright C 2004 Cambridge University Press 1057-0608 DOI: 10.1017/S105706080300001X Aquinas on Attributes BRIAN LEFTOW Oriel College, Oxford Aquinas’ theory of attributes is one of the most obscure, controversial parts of his thought. There is no agreement even on so basic a matter as where he falls in the standard scheme of classifying such theories: to Copleston, he is a resemblance-nominalist1; to Armstrong, a “concept nominalist”2; to Edwards and Spade, “almost as strong a realist as Duns Scotus”3; to Gracia, Pannier, and Sullivan, neither realist nor nominalist4; to Hamlyn, the Middle Ages’ “prime exponent of realism,” although his theory adds elements of nominalism and “conceptualism”5; to Wolterstorff, just inconsistent.6 I now set out Aquinas’ view and try to answer the vexed question of how to classify it. Part of the confusion here is terminological. As emerges below, Thomas believed in “tropes” of “lowest” (infima) species of accidents and (I argue) substances.7 Many now class trope theories as a form of nominalism,8 while 1. F. C. Copleston, Aquinas (Baltimore, MD: Penguin Books, 1955), P. 94. 2. D. M. Armstrong, Nominalism and Realism (New York: Cambridge University Press, 1978), pp. 25, 83, 87. Armstrong is tentative about this. 3. Sandra Edwards, “The Realism of Aquinas,” The New Scholasticism 59 (1985): 79; Paul Vincent Spade, “Degrees of Being, Degrees of Goodness,” in Aquinas’ Moral Theory, ed. -
Guide for the Use of the International System of Units (SI)
Guide for the Use of the International System of Units (SI) m kg s cd SI mol K A NIST Special Publication 811 2008 Edition Ambler Thompson and Barry N. Taylor NIST Special Publication 811 2008 Edition Guide for the Use of the International System of Units (SI) Ambler Thompson Technology Services and Barry N. Taylor Physics Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899 (Supersedes NIST Special Publication 811, 1995 Edition, April 1995) March 2008 U.S. Department of Commerce Carlos M. Gutierrez, Secretary National Institute of Standards and Technology James M. Turner, Acting Director National Institute of Standards and Technology Special Publication 811, 2008 Edition (Supersedes NIST Special Publication 811, April 1995 Edition) Natl. Inst. Stand. Technol. Spec. Publ. 811, 2008 Ed., 85 pages (March 2008; 2nd printing November 2008) CODEN: NSPUE3 Note on 2nd printing: This 2nd printing dated November 2008 of NIST SP811 corrects a number of minor typographical errors present in the 1st printing dated March 2008. Guide for the Use of the International System of Units (SI) Preface The International System of Units, universally abbreviated SI (from the French Le Système International d’Unités), is the modern metric system of measurement. Long the dominant measurement system used in science, the SI is becoming the dominant measurement system used in international commerce. The Omnibus Trade and Competitiveness Act of August 1988 [Public Law (PL) 100-418] changed the name of the National Bureau of Standards (NBS) to the National Institute of Standards and Technology (NIST) and gave to NIST the added task of helping U.S. -
Scalars and Vectors
1 CHAPTER ONE VECTOR GEOMETRY 1.1 INTRODUCTION In this chapter vectors are first introduced as geometric objects, namely as directed line segments, or arrows. The operations of addition, subtraction, and multiplication by a scalar (real number) are defined for these directed line segments. Two and three dimensional Rectangular Cartesian coordinate systems are then introduced and used to give an algebraic representation for the directed line segments (or vectors). Two new operations on vectors called the dot product and the cross product are introduced. Some familiar theorems from Euclidean geometry are proved using vector methods. 1.2 SCALARS AND VECTORS Some physical quantities such as length, area, volume and mass can be completely described by a single real number. Because these quantities are describable by giving only a magnitude, they are called scalars. [The word scalar means representable by position on a line; having only magnitude.] On the other hand physical quantities such as displacement, velocity, force and acceleration require both a magnitude and a direction to completely describe them. Such quantities are called vectors. If you say that a car is traveling at 90 km/hr, you are using a scalar quantity, namely the number 90 with no direction attached, to describe the speed of the car. On the other hand, if you say that the car is traveling due north at 90 km/hr, your description of the car©s velocity is a vector quantity since it includes both magnitude and direction. To distinguish between scalars and vectors we will denote scalars by lower case italic type such as a, b, c etc. -
Outline of Mathematics
Outline of mathematics The following outline is provided as an overview of and 1.2.2 Reference databases topical guide to mathematics: • Mathematical Reviews – journal and online database Mathematics is a field of study that investigates topics published by the American Mathematical Society such as number, space, structure, and change. For more (AMS) that contains brief synopses (and occasion- on the relationship between mathematics and science, re- ally evaluations) of many articles in mathematics, fer to the article on science. statistics and theoretical computer science. • Zentralblatt MATH – service providing reviews and 1 Nature of mathematics abstracts for articles in pure and applied mathemat- ics, published by Springer Science+Business Media. • Definitions of mathematics – Mathematics has no It is a major international reviewing service which generally accepted definition. Different schools of covers the entire field of mathematics. It uses the thought, particularly in philosophy, have put forth Mathematics Subject Classification codes for orga- radically different definitions, all of which are con- nizing their reviews by topic. troversial. • Philosophy of mathematics – its aim is to provide an account of the nature and methodology of math- 2 Subjects ematics and to understand the place of mathematics in people’s lives. 2.1 Quantity Quantity – 1.1 Mathematics is • an academic discipline – branch of knowledge that • Arithmetic – is taught at all levels of education and researched • Natural numbers – typically at the college or university level. Disci- plines are defined (in part), and recognized by the • Integers – academic journals in which research is published, and the learned societies and academic departments • Rational numbers – or faculties to which their practitioners belong. -
Euclidean Spaces and Vectors
EUCLIDEAN SPACES AND VECTORS PAUL L. BAILEY 1. Introduction Our ultimate goal is to apply the techniques of calculus to higher dimensions. We begin by discussing what mathematical concepts describe these higher dimensions. Around 300 B.C. in ancient Greece, Euclid set down the fundamental laws of synthetic geometry. Geometric figures such as triangles and circles resided on an abstract notion of plane, which stretched indefinitely in two dimensions; the Greeks also analysed solids such as regular tetrahedra, which resided in space which stretched indefinitely in three dimensions. The ancient Greeks had very little algebra, so their mathematics was performed using pictures; no coordinate system which gave positions to points was used as an aid in their calculations. We shall refer to the uncoordinatized spaces of synthetic geometry as affine spaces. The word affine is used in mathematics to indicate lack of a specific preferred origin. The notion of coordinate system arose in the analytic geometry of Fermat and Descartes after the European Renaissance (circa 1630). This technique connected the algebra which was florishing at the time to the ancient Greek geometric notions. We refer to coordinatized lines, planes, and spaces as cartesian spaces; these are composed of ordered n-tuples of real numbers. Since affine spaces and cartesian spaces have essentially the same geometric properties, we refer to either of these types of spaces as euclidean spaces. Just as coordinatizing affine space yields a powerful technique in the under- standing of geometric objects, so geometric intuition and the theorems of synthetic geometry aid in the analysis of sets of n-tuples of real numbers. -
Basics of Euclidean Geometry
This is page 162 Printer: Opaque this 6 Basics of Euclidean Geometry Rien n'est beau que le vrai. |Hermann Minkowski 6.1 Inner Products, Euclidean Spaces In a±ne geometry it is possible to deal with ratios of vectors and barycen- ters of points, but there is no way to express the notion of length of a line segment or to talk about orthogonality of vectors. A Euclidean structure allows us to deal with metric notions such as orthogonality and length (or distance). This chapter and the next two cover the bare bones of Euclidean ge- ometry. One of our main goals is to give the basic properties of the transformations that preserve the Euclidean structure, rotations and re- ections, since they play an important role in practice. As a±ne geometry is the study of properties invariant under bijective a±ne maps and projec- tive geometry is the study of properties invariant under bijective projective maps, Euclidean geometry is the study of properties invariant under certain a±ne maps called rigid motions. Rigid motions are the maps that preserve the distance between points. Such maps are, in fact, a±ne and bijective (at least in the ¯nite{dimensional case; see Lemma 7.4.3). They form a group Is(n) of a±ne maps whose corresponding linear maps form the group O(n) of orthogonal transformations. The subgroup SE(n) of Is(n) corresponds to the orientation{preserving rigid motions, and there is a corresponding 6.1. Inner Products, Euclidean Spaces 163 subgroup SO(n) of O(n), the group of rotations. -
Chapter 1 Euclidean Space
Euclidean space 1 Chapter 1 Euclidean space A. The basic vector space We shall denote by R the ¯eld of real numbers. Then we shall use the Cartesian product Rn = R £ R £ ::: £ R of ordered n-tuples of real numbers (n factors). Typical notation for x 2 Rn will be x = (x1; x2; : : : ; xn): Here x is called a point or a vector, and x1, x2; : : : ; xn are called the coordinates of x. The natural number n is called the dimension of the space. Often when speaking about Rn and its vectors, real numbers are called scalars. Special notations: R1 x 2 R x = (x1; x2) or p = (x; y) 3 R x = (x1; x2; x3) or p = (x; y; z): We like to draw pictures when n = 1, 2, 3; e.g. the point (¡1; 3; 2) might be depicted as 2 Chapter 1 We de¯ne algebraic operations as follows: for x, y 2 Rn and a 2 R, x + y = (x1 + y1; x2 + y2; : : : ; xn + yn); ax = (ax1; ax2; : : : ; axn); ¡x = (¡1)x = (¡x1; ¡x2;:::; ¡xn); x ¡ y = x + (¡y) = (x1 ¡ y1; x2 ¡ y2; : : : ; xn ¡ yn): We also de¯ne the origin (a/k/a the point zero) 0 = (0; 0;:::; 0): (Notice that 0 on the left side is a vector, though we use the same notation as for the scalar 0.) Then we have the easy facts: x + y = y + x; (x + y) + z = x + (y + z); 0 + x = x; in other words all the x ¡ x = 0; \usual" algebraic rules 1x = x; are valid if they make (ab)x = a(bx); sense a(x + y) = ax + ay; (a + b)x = ax + bx; 0x = 0; a0 = 0: Schematic pictures can be very helpful. -
Common Core State Standards for MATHEMATICS
Common Core State StandardS for mathematics Common Core State StandardS for MATHEMATICS table of Contents Introduction 3 Standards for mathematical Practice 6 Standards for mathematical Content Kindergarten 9 Grade 1 13 Grade 2 17 Grade 3 21 Grade 4 27 Grade 5 33 Grade 6 39 Grade 7 46 Grade 8 52 High School — Introduction High School — Number and Quantity 58 High School — Algebra 62 High School — Functions 67 High School — Modeling 72 High School — Geometry 74 High School — Statistics and Probability 79 Glossary 85 Sample of Works Consulted 91 Common Core State StandardS for MATHEMATICS Introduction Toward greater focus and coherence Mathematics experiences in early childhood settings should concentrate on (1) number (which includes whole number, operations, and relations) and (2) geometry, spatial relations, and measurement, with more mathematics learning time devoted to number than to other topics. Mathematical process goals should be integrated in these content areas. — Mathematics Learning in Early Childhood, National Research Council, 2009 The composite standards [of Hong Kong, Korea and Singapore] have a number of features that can inform an international benchmarking process for the development of K–6 mathematics standards in the U.S. First, the composite standards concentrate the early learning of mathematics on the number, measurement, and geometry strands with less emphasis on data analysis and little exposure to algebra. The Hong Kong standards for grades 1–3 devote approximately half the targeted time to numbers and almost all the time remaining to geometry and measurement. — Ginsburg, Leinwand and Decker, 2009 Because the mathematics concepts in [U.S.] textbooks are often weak, the presentation becomes more mechanical than is ideal. -
Assisting Students Struggling with Mathematics: Response to Intervention (Rti) for Elementary and Middle Schools
IES PRACTICE GUIDE WHAT WORKS CLEARINGHOUSE AssistingAssisting StudentsStudents StrugglingStruggling withwith Mathematics:Mathematics: ResponseResponse toto InterventionIntervention (RtI)(RtI) forfor ElementaryElementary andand MiddleMiddle SchoolsSchools NCEE 2009-4060 U.S. DEPARTMENT OF EDUCATION The Institute of Education Sciences (IES) publishes practice guides in education to bring the best available evidence and expertise to bear on the types of systemic challenges that cannot currently be addressed by single interventions or programs. Authors of practice guides seldom conduct the types of systematic literature searches that are the backbone of a meta-analysis, although they take advantage of such work when it is already published. Instead, authors use their expertise to identify the most important research with respect to their recommendations, augmented by a search of recent publications to ensure that research citations are up-to-date. Unique to IES-sponsored practice guides is that they are subjected to rigorous exter- nal peer review through the same office that is responsible for independent review of other IES publications. A critical task for peer reviewers of a practice guide is to determine whether the evidence cited in support of particular recommendations is up-to-date and that studies of similar or better quality that point in a different di- rection have not been ignored. Because practice guides depend on the expertise of their authors and their group decisionmaking, the content of a practice guide is not and should not be viewed as a set of recommendations that in every case depends on and flows inevitably from scientific research. The goal of this practice guide is to formulate specific and coherent evidence-based recommendations for use by educators addressing the challenge of reducing the number of children who struggle with mathematics by using “response to interven- tion” (RtI) as a means of both identifying students who need more help and provid- ing these students with high-quality interventions. -
1. Armstrong and Aristotle There Are Two Main Reasons for Not
RECENSIONI&REPORTS report ANNABELLA D’ATRI DAVID MALET ARMSTRONG’S NEO‐ARISTOTELIANISM 1. Armstrong and Aristotle 2. Lowe on Aristotelian substance 3. Armstrong and Lowe on the laws of nature 4. Conclusion ABSTRACT: The aim of this paper is to establish criteria for designating the Systematic Metaphysics of Australian philosopher David Malet Armstrong as neo‐ Aristotelian and to distinguish this form of weak neo‐ Aristotelianism from other forms, specifically from John Lowe’s strong neo‐Aristotelianism. In order to compare the two forms, I will focus on the Aristotelian category of substance, and on the dissimilar attitudes of Armstrong and Lowe with regard to this category. Finally, I will test the impact of the two different metaphysics on the ontological explanation of laws of nature. 1. Armstrong and Aristotle There are two main reasons for not considering Armstrong’s Systematic Metaphysics as Aristotelian: a) the first is a “philological” reason: we don’t have evidence of Armstrong reading and analyzing Aristotle’s main works. On the contrary, we have evidence of Armstrong’s acknowledgments to Peter Anstey1 for drawing his attention to the reference of Aristotle’s theory of truthmaker in Categories and to Jim Franklin2 for a passage in Aristotle’s Metaphysics on the theory of the “one”; b) the second reason is “historiographic”: Armstrong isn’t listed among the authors labeled as contemporary Aristotelian metaphysicians3. Nonetheless, there are also reasons for speaking of Armstrong’s Aristotelianism if, according to 1 D. M. Armstrong, A World of State of Affairs, Cambridge University Press, New York 1978, p. 13. 2 Ibid., p.