全國中小學科展

數學

缺一格也可以─骨牌排列順序數量之探討

在一次偶然的機會中,我們在科學月刊上讀到一篇探討骨牌排列 (Domino Tiling) 問題的文章。文中骨牌排列問題看似單純,但其中卻有許多有趣的性質,因此,我們想對此進行更深入的研究。\r 我們將1x2的骨牌填入特別的方格中,考慮填入的順序並計算其排列情形的數量。由定義的兩個模型SDT(Standard Dominos Tableau) 與「缺一格」的GDT(Good Dominos Tableau) 為基礎,嘗試尋找它們之間的關連性,藉由對應(bijection)的方法,得知在高度的限制為奇數的情況下,SDT與GDT的數量相同,並且,兩者之間的結構有密切關聯。\r 除此之外,在這個研究中,針對SDT在高度不超過三排時,我們建構出了骨牌排列情形與我們架構的「廣義Motkzin路徑」的對應操作流程。接著,我們嘗試探討一般化的SDT與此結果的關聯性,由對應過程的想法,架構出高維度的「廣義Motkzin路徑」,並推測此路徑與SDT之間有緊密的相關性!

由蟲子問題衍生一路領先與Motzkin路徑之對應及推廣

在數學課堂中,老師拋出一道甄試的口試題目,那是一道有關蟲類繁殖過程\r 中,探討子代存在位置及其規律性的題目。此問題引起我們繼續討論的興趣,並\r 試著應用至「一路領先」問題。我們試著改變其形狀來構造「一路領先」的路徑,\r 再擴張其維度來解決任一人數「一路領先」的問題!\r 由於發現Motzkin 數列和三人「一路領先」給定得票數的情況一一對應,我們\r 找到一種對應方法,將Motzkin 路徑和「一路領先」得票過程做一對一的對應!以\r Motzkin 路徑和三人「一路領先」為基礎,我們構造了「立體Motzkin 」,發現其\r 路徑走法數竟和五人「一路領先」得票過程總方法數完全相同!若限制向量(1,0,0)\r 只能出現在xy 平面上,則和四人「一路領先」得票過程一一對應!當我們在網路\r 上搜尋資料時,發現有一種lattice path 的規則和四人「一路領先」的方法數完全\r 一樣!我們一樣找到一種對應規則,讓此走法和四人「一路領先」得票過程一一\r 對應!\r 架構出「立體Motzkin 」後,我們試著架構「n維Motzkin」,發現給定有規律\r 的(2n ?1) 個n維向量,就可以構造出n人的「一路領先」!此方法對解決lattice path\r 和投票問題等有顯著的幫助!

鬼腳圖的數學原理

We can prove 鬼腳圖 have an one-to-one characteristic; it is mean that you can not design a 鬼腳圖 which will make two starting point to the same end. We also can prove you can design any 鬼腳圖 you want; you can predict a result, and you can design a 鬼腳圖 which suit the result, no matter what the result it is. We can design any 鬼腳圖 we want, but it possibly becomes very big and complicated. We develop a method to make it become briefer. According to the method, we make a function that can design the 鬼腳圖 you want in a very short time. You predict a result in computer, and the\r function will design a 鬼腳圖 which suit the result, and it will be the briefest. 吾人已經可以證明鬼腳圖具備一對一的性質,意思就是:不可能從兩個起點開始畫線,最後到同一個終點上。吾人亦證明:鬼腳圖的結果沒有限定:同一組初始條件可以轉換成任何一組結果。而同一組結果也有許多種不同的畫法,顯示鬼腳圖的畫法不具唯一性。即使如此,畫出來的鬼腳圖可能過於複雜,於是吾人又發展出簡化鬼腳圖的方法,可畫出較簡潔的鬼腳圖。吾人並根據這種化簡方式編出一套程式,只要將欲得的結果輸入,電腦就可以畫出最簡潔的鬼腳圖。

平面上三點集中度判別法之探討

關於平面上若干點的集中度之定義,一直很少有人予以仔細的探討,因為判別的方法有很多種。本研究是以平面上三點所構成的三角形之三頂點作討論,分別以三角形的面積、周長,內心、外心和重心至三頂點距離,三點的標準差及平均差的概念,作為不同的判別方式,並以動態幾何化版GSP模擬不同的判斷方法做為研究,在利用統計學上的方法,找出哪一種定義方式最為適合、誤差最少的判斷方法。There are many ways to determine the centralness of three dots on a plane; however, no definition study has been applied. In this study, we focus our interests on the entralness of three vertices of a triangle formed from three dots on a plane. Various methods such as the relationship of area, and the distance of the triangle to the centralness of three dots, the distance from the interior point, exterior point, the barycenter to the vertices of triangle, and the standard error and differences average obtained from three dots were determined with a dynamic geometry software GSP, and a statistic method was used to find a least error way to determine the centralness of three dots on a plane.

省錢大作戰-探討籬笆價格和所圍面積的關係

本研究探討在給定範圍的面積下,以最省錢的方式用籬笆圍出最大的矩形土地,其中矩形的邊長為正整數,且矩形對邊使用相同單價之材質的籬笆,但相鄰邊使用不同單價之材質的籬笆。我們希望透過轉換,將單價不同的情況回歸到單價相同的情況,以便完整的解決這個問題。\r 藉由改變邊長,將 轉換成 ,使問題轉換成相鄰邊之單價相同的情況;但是經過運算找出的最佳解 轉換回 後卻不一定符合「整數邊長」的要求(即 和 不一定是整數)。為了解決這點,我們重新以不同的角度探討單價相同的情形,以找出整數的最佳解。\r 最後我們發現,若 和 切線斜率的差值大於或等於1,則 坐標愈近 的解愈佳,而在差值小於1的範圍內,我們提出一個檢驗法,可以找到整個問題的最佳解,同時讓此最佳解 轉換回 後仍符合「整數邊長」的要求,進而解決問題。

遞迥數列及渾沌現象

給定一個P∈(0,1),令k0=0, p0=p,定義k1為能使 的最小正整數k,而 ; 相同的,對於給定的kn-1, kn 為能使的最小正整數k, 。若存在kn 使得,則稱p∈ In; 若對於所有n 與kn ,,則稱p∈ I∞。如此區間(0,1)可分解成集合I1,I2,…,I∞。

移動棋子問題的致勝策略

We consider a game played with chips on a strip of squares. The squares are labeled, left to right, with 1, 2, 3, . . ., and there are k chips initially placed on distinct squares. Two players take turns to move one of these chips to the next empty square to its left. In this project, we study four different games according to the following \r rules: Game A: the player who places a chip on square 1 wins;Game B: the player who places a chip on square 1 loses;Game C: the player who finishes up with chips on 12 . . . k wins;Game D: the player who finishes up with chips on 12 . . . k loses. After studying the cases k = 3, 4,5 and 6 for Game A and the relation among these four games, we are led to discover the winning strategy of each game for any positive integer k. The strategies of Games A, B and C are closely related through a forward or backward shifting in position. We also found that such strategies are similar to the type of Nim game that awards the player taking the last chip. Game D is totally different from the rest. To solve this game, we investigate the Nim game that declares the player taking the last chips loser. Amazingly, the strategies of two Nim games can be concisely linked by two equations. Through these two Nim games, we not only find the winning strategy of Game D but also the precise relation between Game D and all others.\r 去年我研究一個遊戲:有一列n個的方格中,從左至右依序編號為1,2,3,....n。在X1個、第X2個、第X3個格子中各放置一個棋子。甲乙二個人按照下列規則輪流移動棋子:\r 一、甲乙兩個人每次只能動一個棋子(三個棋子中任選一個)。遊戲開始由甲先移動動棋子。二、甲乙兩個人每次移動某一個棋子時,只能將這個棋子移至左邊最近的空格(若前面連續有P個棋時可以跳過前面的P個棋子而且只能跳一次),而且每個方格中最多只能放一個棋子。\r 研究這個遊戲問題時,我討論四種不同"輸贏結果"的規定:甲乙兩個人中,A誰先將三個棋子中任意一個棋子移到第一個方格,誰就是贏家。B誰先將三個棋子中任意一個棋子移到第一個方格,誰就是輸家。C誰先不能再移動任何棋子,誰就是輸家。D誰先不能再移動任何棋子,誰就是贏家。\r 當"輸贏結果"的規定採用ABCD時─我們稱為遊戲ABCD。今年我將把這個遊戲問題中棋子的個數由三個推廣到一般K個情形之後,再繼續研究遊戲的致勝策略,同時也將研究遊戲ABCD之間的關係。

Double Pedal Curve

設Γ為一平面曲線而 P 為一定點 , 自P 向Γ所有的切線作對稱點,則所有對稱點所成的圖形Γ1 稱為曲線Γ對定點P 的double pedal curve , Γ1 對定點P 的double pedal curve Γ2 稱為曲線Γ對定點P 的2-th double pedal curve , Γ2 對定點P 的double pedal curve Γ3 稱為曲線 Γ對定點P 的3-th double pedal curve ,…… 。以下是本文主要的結果:結論A:當Γ為一圓形而P 為圓上一點時 , 計算其n−th double pedal curve 的方程式。結論B:當Γ為任意平滑的參數曲線而P 為任意一點時 , Γ的 double pedal curve 的切線性質。結論C:當Γ為任意平滑的參數曲線而P 為(0,0)時, 計算其n−th double pedal curve 的方程式。 Given a plane curve Γand a fixed point P ,the locus of the reflection of P about the tangent to the curveΓis called the double pedal curve of Γwith respect to P.We denote Γ1 as the double pedal curve of Γwith respect to P, Γ2 as the double pedal curve of Γ1 with respect to P , Γ3 as the double pedal curve of Γ2 with respect to P ,and so on , we call Γn the n-th double pedal curve of Γwith respect to P. If Γ is a circle, and P is a point on the circle, we got the parametric equation of the n−th double pedal curve of Γ with respect to P. And, for any parametric plane curve Γ; we got the method to draw the tangent of the double pedal curve of Γ.

空心球的奧秘

上體育課的時候看到同學投空心球(籃球在沒有碰著籃框的情況下進入籃中),覺得好厲害。因此,我們利用相關的數學知識與運動原理來討論籃球投出後的運行軌跡,以及影響其命中率的相關因素。我們得知籃球的運行軌跡是一條拋物線,並求出其二次方程式;並利用標準籃球直徑與籃框直徑找出籃球進入籃框的最小入射角。若要提高命中率,必須考慮籃球投出時的投射角、初速度、籃球投出時的高度以及籃球與籃框水平距離之間的相關影響。此外,我們藉由電腦軟體列出相關數據提供作為實際投籃時的參考,並藉此進一步分析上述因素如何影響籃球運行軌跡以及如何提高投籃的命中率。Those who always shoot nothing but the net in basketball games were always heroes to me. I have being thinking for a long time how to become a person of that kind. For this, we investigated the trajectory of shooting a basketball and the factors to increasing the field goal percentages through our knowledge on mathematics and physics. We have obtained that the trajectory is in fact a parabola and, we further, found its quadratic equation. We also derived the minimal incident angle from the diameters of the standard basketball and hoop as well as the quadratic equation we have found. To raise the field goal percentages, some important factors must be taken into consideration, such as the vertical and horizontal distance between the basketball and the hoop, the incident angle and the initial velocity of shooting. Finally, we provide some concerning data for reference, and analyzed how the important factors we have mentioned above have affected our basketball trajectory and how, of the most importance, to increase the field goal percentages

圓來如此─西姆松「圓」的研究

若從一個三角形的外接圓上取一點,作其對三角形三邊的垂足,我們知道這三點共線,是為西姆松線。\r 那麼當此點不在圓周上的情形呢?自平面上一點對一三角形的三邊分別做垂線,得到三垂足,並作此三垂足的外接圓,我定義其為:此點對此三角形的西姆松圓。這篇作品主要成果便是對西姆松圓的研究。透過不斷的研究,發現了許多關於西姆松圓的神奇性質,並得到了一些結果,主要的研究方向:討論共點、共圓、相似。\r 這篇報告是循序漸進的,後面的結果常用到前面的知識為基礎。此篇另一特點是:全篇的證明皆是自已給出的,採用方法皆為一般幾何證明,而沒有用到解析證明。\r 在研究過程中也得到關於著名的費爾巴哈定理及大上茂喬定理的另一種證明。