全國中小學科展

六圓定理

科展類別

臺灣國際科展

屆次

2008年

科別

數學科

學校名稱

國立新竹科學工業園區實驗高級中學

指導老師

莊添丁

作者

曾士豪

關鍵字

圓 切圓

摘要或動機

在實驗中學2007 年校內科展,參展作品《三角形中的切圓》的研究中,研究三角形內的切圓時,發現連續切圓的圓心與拋物線的軌跡有關。於是去查資料,在偶然的情況下,翻閱《平面幾何中的小花》時,接觸了「六圓定理」。因為覺得這問題非常有趣,於是便著手證明(見報告內文)。 又發現,當移動六個圓中的起始圓時,總是在某種情況下,六個圓會重合成三個圓。繼續研究其重合的狀況,發現了馬爾法蒂問題(Malfatti's Problem)的一種代數解法。 當我試著推廣六圓定理至多邊形時,發現奇數邊的多邊形似乎也有如六圓定理般圓循環的狀況,於是著手證明,但目前尚未證明成功。而偶數邊的多邊形則無類似的結果。 ;In 2007 National Experimental High School Science Exhibition, one of the exhibit works, "Inscribed Circles in Triangles", shows that the centers of the consecutive inscribed circles has something to do with the parabola's trajectory. To learn more about inscribed circles and parabolas, I referred to literature. By accident, I am faced with the problem on six circles theorem, in the book The Small Flower of Plane Geometry(平面幾何中的小花). Out of my interest in this problem, I tried to prove it. The other results are as follows: With the initial circle of six circles moved, in certain circumstances, the six circles merge into three. Further in studying this coincidence leads to an algebraic method to solve the Malfatti's Problem. Applying six circles theorem to the odd-number-sided polygons exists the same characteristic. It indicates that the inscribed circles will form a cycle. However, it hasn’t been successfully proven. The even-number-sided polygons show no similar results.

六圓定理

Adobe Reader(Pdf)檔案