Σn=1∞(n/(Cn2n))=√(x/(4-x)3) (√x(4-x) + 4sin-1(√x/2))與其相關的無窮級數
本文從一個博奕遊戲談起,探討遊戲的期望值得到一無窮級數Σn=1∞n/Cn2n 並嘗試用相關的數學概念與方法思考,首先處理問題Σn=1∞n/Cn2n 與Σn=1∞n2/Cn2n 的值,過程中利用了Σn=1∞n/Cn2n 函數與Σn=1∞n2/Cn2n 函數的性質將欲求之無窮級數轉化成積分或微分方程式的型態,再利用奧斯特洛格拉德斯基積分方法解出所求。 為了更有效率的得到相關之無窮級數,引進了微積分工具中之冪級數的概念,輔以微分方程式公式解求出了 f(x)=Σn=1∞Xn/Cn2n =√x/(4-x)3 (√x(4-x) + 4sin-1(√x/2)), x∈(-4,4), 進而推廣、延伸與其相關的一系列無窮級數,並利用導函數f'(x)求得 Σn=1∞n·2n-1/Cn2n的值。 接下來討論與f'(x)相關的無窮級數,發現可利用f(x)的高階導函數透過迭代方式得到Σn=1∞nm/Cn2n的值,其中m為任意正整數,歸納這些級數後可以應用在本文之博奕遊戲,讓獎金的選擇更富有變化性。 最後觀察f(x)與卡塔蘭數列{Cn}的倒數所構成之冪級數有所關聯,解出 Σn=1∞Xn/Cn的收斂函數後求出了Σn=1∞1/Cn的值以及{1/Cn}的偶數項與奇數項的和。
Development of a rotor blade with optimized aerodynamics to propel a quadcopter
Sustainable mobility concepts are playing an increasingly important part in today's social developments. As a promising mode of future transportation, quadcopters play a special role, and their further development and optimization is being advanced along many disciplines. Even in my hometown of Zurich this trend has not passed by without leaving its marks. Since 2019, the Swiss National Postal Service has been testing autonomous means of transport together with the Zurich University Hospital as part of a pilot project. However, quadcopters are not exclusively used for transportation purposes. Geologists use them for landscape modeling and the insurance industry utilizes them for damage assessment. Quadcopters have also become an integral part of photography and agriculture, where they are used for pest control, for example [2]. I first became intensively involved with quadcopters in 2017, when I received a hobby model for my birthday in the form of the Mavic Pro from the Chinese company Da-Jiang Innovations Science and Technology Co., Ltd (DJI). In October of the same year, I completed an internship in the biofluid mechanics department of the Institute for ImplantTechnology and Biomaterials e.V., where I studied the aerodynamics of airfoils. With my Mavic Pro in my backpack, I had the idea to develop and prototype my own functional rotor for my quadcopter as part of my upcoming Swiss Matura thesis paper. The rotor would be considered functional if it generates enough lift to keep the quadcopter hovering. The focus of this project was the investigation of aerodynamic properties. The influence of other factors, such as the material used, was not the primary focus of the work and therefore not investigated in detail.