• 충청수학회지
• /
• 제29권1호
• /
• pp.123-135
• /
• 2016

In this article, we introduce the transforms of Pythagorean and quadratic means of weighted shifts. We then explore how the transforms of weighted shifts behaves, in comparison with the Aluthge transform.

• 대한수학교육학회지:학교수학
• /
• 제4권3호
• /
• pp.401-413
• /
• 2002

The Pythagorean theorem is one of the most important theorem which appeared in school mathematics. Allowing our pupils to rediscover it in classroom, we must know how this theorem was discovered and proved. Further, we should recompose that historical knowledge to practical program which might be suitable to them So, firstly this paper surveyed the history of mathematics on discovering the Pyth-agorean theorem. This theorem was known to many ancient civilizatons: There are evidences that Babylonian and Indian had the knowledges on the relationship among the sides of a right triangle. In Zhoubi suanjing, which was ancient Chinese text book, was the proof of the Pythagorean theorem in special case. And then this paper proposed a teaching program that is composed following five tasks : 1) To draw up squares on geo-board that are various in size and shape, 2) To invent squares that are n-times bigger than a given square, 3) Discovering the Pyth-agorean theorem through the previous activity, 4) To prove the Pythagorean theorem in special case, 5) To prove the Pythagorean theorem in general case.

• Journal of applied mathematics & informatics
• /
• 제23권1_2호
• /
• pp.73-86
• /
• 2007

The general stereographic projection which maps a point on a sphere with arbitrary radius to a point on a plane stereographically and its inverse projection have the pythagorean-hodograph (PH) preserving property in the sense that they map a PH curve to another PH curve. Upon this fact, for given spatial $C^1$ Hermite data, we construct a spatial PH curve on a sphere that is a $C^1$ Hermite interpolant of the given data as follows: First, we solve $C^1$ Hermite interpolation problem for the stereographically projected planar data of the given data in $\mathbb{R}^3$ with planar PH curves expressed in the complex representation. Second, we construct spherical PH curves which are interpolants for the given data in $\mathbb{R}^3$ using the inverse general stereographic projection.

• 한국수학교육학회지시리즈A:수학교육
• /
• 제39권1호
• /
• pp.21-36
• /
• 2000

The purpose of the study was to investigate the effects of the geoboard activities in understanding the Pythagorean Theorem. Five groups of middle school students were involved in the study. The research questions of the study were followings: 1)What are the differences in understanding and attitudes among students those who revealed the various levels of achievement when geoboards were introduced in learning the Pythagorean Theorem. 2)What was the effect of the geoboard activity in introducing the Pythagorean Theorem and solving relevant problems? 3)What would be the impression of geoboard activity for those who already knew the Pythagorean Theorem? 4)What would be the effects of interaction in geoboard activities? 5)What was the effect of the geoboard activity in recovering the Pythagorean Theorem, and applying the theorem. The result of the study revealed the positive effects of geoboard activities throughout the research questions although there were differences among various levels of students and groups.

• 한국수학사학회지
• /
• 제32권5호
• /
• pp.241-255
• /
• 2019

The proposition that the parallel axiom and the Pythagorean theorem are equivalent in the Hilbert geometry is true when the Archimedean axiom is assumed. In this article, we examine some specific plane geometries to see the existence of the non-archimidean Hilbert geometry in which the Pythagorean theorem holds but the parallel axiom does not. Furthermore we observe that the Pythagorean theorem is equivalent to the fact that the Hilbert geometry is actually a semi-Euclidean geometry.

• 한국수학사학회지
• /
• 제34권6호
• /
• pp.205-223
• /
• 2021

It has been argued that as for the origin of the Pythagorean theorem, the theorem had already been discovered and proved before Pythagoras, and the historical records of ancient mathematics have confirmed various uses of this theorem. The purpose of this study is to examine the relevance of its name caused by Eurocentrism and the weakness of its use in Korean school mathematics and to seek improvements from a critical point of view. To this end, the Pythagorean theorem was reviewed from the perspectives of the history of mathematics and mathematics education. In addition, its name in relation to objective mathematical contents regardless of any specific civilization and its use as a starting point for teaching the theorem in school mathematics were suggested.

• East Asian mathematical journal
• /
• 제31권4호
• /
• pp.459-481
• /
• 2015

In this study, we investigated whether the theorem is established even if we replace a 'square' element in the Euclidean proof of the Pythagorean theorem with different figures. At this time, we used different figures as equilateral, isosceles triangle, (mutant) a right triangle, a rectangle, a parallelogram, and any similar figures. Pythagorean theorem implies a relationship between the three sides of a right triangle. However, the procedure of Euclidean proof is discussed in relation between the areas of the square, which each edge is the length of each side of a right triangle. In this study, according to the attached figures, we found that the Pythagorean theorem appears in the following three cases, that is, the relationship between the sides, the relationship between the areas, and one case that do not appear in the previous two cases directly. In addition, we recognized the efficiency of Euclidean proof attached the square. This proving activity requires a mathematical process, and a generalization of this process is a good material that can experience the diversity and rigor at the same time.

• Journal of the Korean Data and Information Science Society
• /
• 제28권2호
• /
• pp.309-316
• /
• 2017

야구에서 승률 추정은 매우 중요한 문제이며 현재 이 분야에 대한 연구가 활발하게 진행되고 있다. 쌍별 승률추정은 팀대 팀의 경기결과를 이용하여 전체 승률을 추정하는 방법으로써 각 팀들의 추정된 승률의 합이 상수가 된다는 타당성을 가진다. 본 연구에서는 한국프로야구에서 피타고라스 승률과 선형 승률에 쌍별 추정을 적용하고 효율성을 RMSE와 MAD를 이용하여 살펴보았다. 사용된 데이터는 2013년부터 2016년 사이의 모든 한국프로야구 팀대 팀 기록이며, 그 결과 쌍별 피타고라스 추정이 기존의 방법들보다 RMSE와 MAD 측면에서 바람직하다고 간주되었다. 또한 쌍별 피타고라스 추정에 사용되는 바람직한 지수 값의 결정에 대하여 설명하였으며 추정에 사용된 지수 값의 변화에 따른 RMSE와 MAD의 차이는 크지 않음을 알 수 있었다.

• Journal of the Korean Data and Information Science Society
• /
• 제26권3호
• /
• pp.653-659
• /
• 2015

야구의 피타고라스 정리는 야구의 승률을 추정하는 방법으로 오랜 기간 동안 타당성이 입증되고 또 활용되고 있다. 본 연구에서는 2005년부터 2014년 사이의 한국프로야구 팀대 팀 전체기록을 이용하여 실제승률과 피타고라스 정리에 의해 추정된 기대승률의 차이가 발생하는 원인을 회귀모형을 이용하여 살펴보았다. 기대승률과 실제승률의 차이가 큰 경우는 득점과 실점의 분포가 특이하다는 가정아래에서 종속변수는 실제승률과 기대승률의 차이, 독립변수로는 게임당 득점 및 실점의 평균, 표준편차, 변동계수를 각각 이용하였다. 그 결과 실제승률과 기대승률의 차이에는 게임당 실점의 표준편차와 변동계수가 영향을 미치며 게임당 득점의 영향은 없는 것으로 나타났다.

• Journal of the Korean Data and Information Science Society
• /
• 제25권3호
• /
• pp.493-499
• /
• 2014

야구의 승률은 총득점의 제곱을 총득점의 제곱과 총실점의 제곱의 합으로 나눈 것으로 추정된다는 야구의 피타고라스 정리에 대하여 많은 연구들이 활발하게 진행되고 있다. 본 연구에서는 피타고라스 정리에 사용되는 지수에 대한 새로운 추정방법을 제안하며 평균제곱오차의 제곱근 (root mean squared error; RMSE)을 이용하여 널리 알려진 추정방법들과 상대적 효율성을 비교하였다. 사용된 데이터는 1982년부터 2013년 사이의 모든 한국프로야구 기록이며, 그 결과 제안된 방법은 기존의 방법보다 RMSE 관점에서 바람직하다고 간주된다.