• Communications of Mathematical Education
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• v.19 no.3 s.23
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• pp.485-502
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• 2005

한 가지 문제에 대한 다양한 풀이 방법을 탐색하는 것은 수학적 대상의 성질을 발명, 일반화하는 것 뿐만 아니라, 학생들의 지적인 유창성 및 유연성 계발, 수학에 대한 심미적 가치의 함양을 위한 의미 있는 교수학적 경험을 제공할 수 있을 것이다. 본 연구에서는 고등학교 '미분과 적분'에 제시된 사인의 덧셈정리에 대한 다양한 증명 방법을 제시하고, 이를 분석하여 수학교수학적으로 의미로운 시사점을 도출하였다. 이를 통해, 사인의 덧셈정리에 대한 새로운 증명 방법의 탐색, 사인의 덧셈정리의 수학교수학적 활용의 다양한 가능성을 모색할 수 있는 기초자료를 제공할 것이며, 제시된 증명 방법들은 '미분과 적분'의 지도에서 심화학습 자료로도 활용할 수 있을 것이다.

• Communications of Mathematical Education
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• v.24 no.2
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• pp.325-344
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• 2010

The purpose of this study is to investigate what influences students' preferences on empirical and deductive proofs and find their relations. Although empirical and deductive proofs have been seen as a significant aspect of school mathematics, literatures have indicated that students tend to have a preference for empirical proof when they are convinced a mathematical statement. Several studies highlighted students'views about empirical and deductive proof. However, there are few attempts to find the relations of their views about these two proofs. The study was conducted to 47 students in 7~9 grades in the transition from empirical proof to deductive proof according to their mathematics curriculum. The data was collected on the written questionnaire asking students to choose one between empirical and deductive proofs in verifying that the sum of angles in any triangles is $180^{\circ}$. Further, they were asked to provide explanations for their preferences. Students' responses were coded and these codes were categorized to find the relations. As a result, students' responses could be categorized by 3 factors; accuracy of measurement, representative of triangles, and mathematics principles. First, the preferences on empirical proof were derived from considering the measurement as an accurate method, while conceiving the possibility of errors in measurement derived the preferences on deductive proof. Second, a number of students thought that verifying the statement for three different types of triangles -acute, right, obtuse triangles - in empirical proof was enough to convince the statement, while other students regarded these different types of triangles merely as partial examples of triangles and so they preferred deductive proof. Finally, students preferring empirical proof thought that using mathematical principles such as the properties of alternate or corresponding angles made proof more difficult to understand. Students preferring deductive proof, on the other hand, explained roles of these mathematical principles as verification, explanation, and application to other problems. The results indicated that students' preferences were due to their different perceptions of these common factors.

• Communications of Mathematical Education
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• v.18 no.1 s.18
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• pp.123-136
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• 2004

수학이라는 학문 자체가 몇 가지 정의와 공리로부터 논리 법칙을 이용하여 명제나 정의를 유도하고 확장하는 공리적인 성격을 지니고 있기 때문에 그러한 논리 전개의 진위 여부를 판별해주는 증명은 수학에서 아주 중요하다. 특히 중학교 2학년 학생들은 정의와 성질을 이용한 증명을 다루는데 정의와 성질의 역할을 제대로 구분하지 못할 경우 증명 자체가 어려워진다. 학생들을 가르치다 보면 정의와 성질을 구분하지 못하고 증명과정에서 정의와 성질이 어떤 역할을 하는지 제대로 알지 못하는 경우가 종종 있다. 본 연구에서는 정의와 성질의 구분 실태를 조사하고, 정의와 성질의 구분에 어려움이 있는 학생들을 대상으로 증명과정에서 정의와 성질의 역할에 대하여 학생들이 겪는 어려움과 처치과정의 사례 연구를 통하여 분석함으로써 증명 교육의 바람직한 방안을 모색하고자 한다.

• Journal of Educational Research in Mathematics
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• v.24 no.3
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• pp.359-374
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• 2014

Students' difficulties and errors in relation to mathematical proofs are worth while to say one of the dilemmas in mathematics education. The potential elements of their difficulty are scattered over the process of proving in geometry as well as algebra. This study aims to investigate whether middle school students understand the context of algebraic proof including literal expressions. We applied 24 third-grade middle school students a test item which shows a proof including a literal expression and missing the conclusion. Over the half of them responded wrong answers based on only the literal expression without considering its context. Three of them were interviewed individually to show their thinking. As a result, we could find some characteristics of their thinking including the perspective on proof as checking the validity of algebraic expression and the gap between proving and understanding of proof etc. From these, we also discussed about several didactical implications.

• Journal for History of Mathematics
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• v.17 no.3
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• pp.93-108
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• 2004

In this article we study on various proofs of the Steiner-Lehmus theorem(any triangle that has two equal angle bisectors is isosceles). We suggest 6 geometric proofs and 3 algebraic proofs of the theorem in detail, analyze these proofs, extract related theorems, proof ideas.

• Communications of Mathematical Education
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• v.23 no.3
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• pp.887-921
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• 2009

Pythagorean theorem is one of mathematical contents which is widely used during human culture have developed. There are many historial records related to Pythagorean theorem made by Babylonian, Egyptian, and Mesopotamian. The theorem has the important meaning for mathematics education in secondary school education. Along with the importance of the proof itself, diverse proof methods and ideas included in their methods are also important since the methods improve students' ability to think mathematics. Hence, in this paper, we classify and analyze 390 proof methods published in the book "All that Pythagorean theorem" and other materials. Based on the results we derive educational meaning in mathematics with respect to main idea of the proof, the preliminaries of the study, and study skills used for proof.

• Journal for History of Mathematics
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• v.21 no.3
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• pp.127-142
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• 2008

In this paper, we introduce four different approaches of proving Cayley formula, which counts the number of trees(acyclic connected simple graphs). The first proof was done by Cayley using recursive formulas. On the other hands the core idea of the other three proofs is the bijective method-find an one to one correspondence between the set of trees and a suitable family of combinatorial objects. Each of the three bijection gives its own generalization of Cayley formula. In particular, the last proof, done by Seo and Shin, has an application to computer science(theoretical computation), which is a typical example that pure mathematics supply powerful tools to other research fields.

• Journal of Educational Research in Mathematics
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• v.27 no.2
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• pp.191-205
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• 2017

The purpose of this study is to investigate the types and characteristics of the Seventh Graders' proofs. Harel, & Sowder's proof schemes were used to analyze the subjects' responses. As a result of the study, there was a difference in the type of proof schemes used by the students depending on the academic achievement level. While the proportion of students using a transformative proof scheme decreased from the top to the bottom, the proportion of students using inductive (measure) proof scheme increased. In addition, features of each type of proof schemes were shown, such as using informal codes in the proof process, and dividing a given picture into a specific ratio in the problem. Based on this, we extracted four meaningful conclusions and discussed implications for proof teaching and learning.

• Communications of Mathematical Education
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• v.18 no.2 s.19
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• pp.251-263
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• 2004

피타고라스 정리와 코사인 제 2법칙 사이에는 어떤 관계가 있을까. 현재 우리의 교육과정에서는 피타고라스 정리는 중학교 3학년에서 코사인 제 2법칙은 고등학교 1학년에서 배운다. 그런데, 이 두 가지 수학적 사실 사이에는 밀접한 관계가 있다. 피타고라스 정리의 확장으로서 코사인 제 2법칙을 유도할 수 있다는 것이다. 코사인 제2법칙이 소개되어진 최초의 문헌은 Euclid의 <원론>으로 거슬러 올라간다. <원론>에 소개되어진 코사인 제 2법칙의 증명방법으로 시작하여 수 천년 동안 증명되어온 다양한 증명방법을 소개하고자 한다. 특히, 직각삼각형과 원이라는 큰 틀을 바탕으로 코사인 제 2법칙의 증명 방법에 대해 고찰하고, 그 외 다양한 증명방법을 분석하고자 한다.

• Communications of Mathematical Education
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• v.13 no.1
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• pp.265-274
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• 2002

이 프로젝트는 수학 수업 중 ‘추론’과 ‘증명’에 관련된 "문제해결과정"에 관심을 가지고, 처음 증명문제를 접하는 독일 7학년 학생들을 대상으로 문제해결능력에 필요한 요인들, 즉, 문제 해결을 위한 수학적 기본지식, 해결된 문제에 대한 인지정도, 논리적 사고 등을 관찰 분석하고 수학교사의 수학에 대한 신념(Beliefs)과 수업 방식이 학생들의 문제해결에 미치는 영향을 조사하는 것에 그 목적을 둔다. 이 프로젝트의 일부의 결과로써, 본 논문에서는 학생들 개개인의 문제해결과정과 그 능력, 그리고 수학에 대한 신념을 서술하고, 수학교사와 학생들의 서로 다른 수학에 대한 신념을 비교 분석한다.