• The Mathematical Education
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• v.45 no.3 s.114
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• pp.367-373
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• 2006

This study suggests that it is necessary to prove that the values of three areas of a triangle, which are obtained by the multiplication of the respective base and its corresponding height, are the same. It also seeks to deeply understand the meaning of Area formula of triangles by exploring some questions raised in the analysis of the proof. Area formula of triangles expresses the invariance of congruence and additivity on one hand, and the uniqueness of parallel line, one of the characteristics of Euclidean geometry, on the other. This discussion can be applied to introducing and developing exploratory learning on area in that it revisits the ordinary thinking on area.

• East Asian mathematical journal
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• v.36 no.2
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• pp.131-146
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• 2020

The isoperimetric problem is a well-known optimization problem from ancient Greek. Among plane figures with the same perimeter, which is the largest area surrounded? The answer to the question is circle. Zenodorus and Steiner's pure geometric proofs, which left a lot of achievements in this matter, looked beautiful with ideas at that time. But there was a fatal flaw in the proof. The weakness is related to the existence of the solution. In this paper, from a view of the existence of the solution, we investigate proofs of Zenodorus and Steiner and get educational implications.

• The Mathematical Education
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• v.37 no.1
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• pp.35-54
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• 1998

Half century has passed since Korean peninsula was divided into South and North Korea. Now a days, there are many differences of politics, economy, culture and education between South and North Korea. Especially mathematics education in which I am interested has a lot of changes and differences. This is proved true by defects' proof. For those reasons, I compared South Korea's education ideology, goal and system, and goals of mathematics education with North Korea's. I compared geometric(1-4 years, published by Pyong-yang Educational Book Publication Co. 1991) of mathematics texts(1-6 years) which are used in the secondary school with mathematics text of South Korea in contents and organization of them. As a result of this comparison, education ideology and goal are distinctly different from those of South Korea because of the difference of pursuing humanity. In North Korea, the curriculum is very strict without autonomy. There are 1283 mathematics classes which are occupied 19% for six years during the secondary school. The contents are very similar, but there is a little difference in the definition of a term. The problems which praise Kim Il-sung and his son and reveal loyalty to them were found, and there were a lot of problems in order to promote hostile feeling against U.S.A and South Korea, too. In conclusion, mathematics education of Korean peninsula should be reunified in the fields of the terms and contents at first.

• Research in Mathematical Education
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• v.17 no.2
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• pp.133-152
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• 2013

In this research, we investigated students' understanding of the definitions of sequence of continuous functions and its uniform convergence. We selected three female and three male students out of the senior class of a university and conducted questionnaire surveys 4 times. We examined students' concept images of sequence of continuous functions and its uniform convergence and also how they approach to the right concept definitions for those through several progressive questions. Furthermore, we presented some suggestions for effective teaching-learning for the sequences of continuous functions.

• Communications of Mathematical Education
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• v.19 no.4 s.24
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• pp.699-713
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• 2005

In this paper, we attempted to find out the meaning of several means and inequalities, their relationships and proposed the effective ways to teach them in college mathematics classes. That is, we introduced 8 proofs of arithmetic-geometric mean equality to explain the fact that there exist diverse ways of proof. The students learned the diverseproof-methods and applied them to other theorems and projects. From this, we found out that the attempt to develop the students' logical thinking ability by encouraging them to find out diverse solutions of a problem could be a very effective education method in college mathematics classes.

• Research in Mathematical Education
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• v.14 no.3
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• pp.211-218
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• 2010

It is a truism that mathematics is about relations (cf. [Halford, G. S. (1999). The properties of representations used in higher cognitive processes: Developmental implications. In: Sigel, I. E. (Ed.), The Development of Mental Representation: Theories and Applications (pp. 147-168). Mahwah, New Jersey: Erlbaum]). In this article we are considering few problems related to the Viviani's and Routh's Theorems. All Problems are connected by the relation which exists between the distances of the point inside the triangle to it sides. We show how reasoning about the relations could lead the student's problem solving process and give easy to understand solutions of the problems. Among the problems being considered are the proof of the Converse to Viviani's Theorem, the formulas for areas of all figures formed by the sides of triangle and its cevians.

• The Mathematical Education
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• v.47 no.4
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• pp.437-445
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• 2008

On the basis of the meaning and general process of geometric proof through transformation concept and understanding the geometric properties of linear transformation, this study showed that the centroid of geometrical figure and certain properties of a parabola and an ellipse in school mathematics can be explained as a conservative properties through linear transformation. From an educational perspective, this is a good example of showing the process of how several existing individual knowledge can be reorganized by a mathematical concept. Considering the fact that mathematical usefulness of linear transformation can be revealed through an invariable and conservation concept, further discussion is necessary on whether the linear transformation map included in the former curriculum have missed its point.

• Research in Mathematical Education
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• v.18 no.1
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• pp.1-29
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• 2014

When taught the precise definition of ${\pi}$, students may be simply asked to memorize its approximate value without developing a rigorous understanding of the underlying reason of why it is a constant. Measuring the circumferences and diameters of various circles and calculating their ratios might just represent an attempt to verify that ${\pi}$ has an approximate value of 3.14, and will not necessarily result in an adequate understanding about the constant nor formally proves that it is a constant. In this study, we aim to investigate prospective teachers' conceptual understanding of ${\pi}$, and as a constant and whether they can provide a proof of its constant property. The findings show that prospective teachers lack a holistic understanding of the constant nature of ${\pi}$, and reveal how they teach students about this property in an inappropriate approach through a proving activity. We conclude our findings with a suggestion on how to improve the situation.

• Proceedings of the Korea Database Society Conference
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• 2008.05a
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• pp.163-182
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• 2008

In this study, the survey from nationwide universities, e-learning service companies, and students who take e-learning courses was proof-analyzed. Sufficiency, variety, usability, accessability, and interaction with instructors were the criteria for analyzing the effectiveness of e-learning education. For this, the factors about effectiveness of e-learning education between the SCORM contents users group and normal contents users group were compared and analyzed. The differences between those two groups were appeared.

• Communications of Mathematical Education
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• v.23 no.4
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• pp.1059-1078
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• 2009

In this paper we study metric equalities related with distance between excenter and other points of triangle. Especially we find metric equalities between excenter and incenter, circumcenter, center of mass, orthocenter, vertex, prove these formulas, and transform these formulas into new formula containing another elements of triangle. We in detail describe proof process of these equalities, indicate references of some formulas that don't exist within secondary school curriculum.