Ibn Sahl’s machines to draw conics continuously

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• 作者：Franco Ghione
• 关键词：Museum ; Oman ; History of science ; Conics ; Ibn Sahl
• 刊名：Lettera Matematica
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：4
• 期：2
• 页码：79-82
• 全文大小：1,118 KB
• 刊物主题：Mathematics, general; Theoretical, Mathematical and Computational Physics; Mathematical Methods in Physics; Applications of Mathematics; History of Mathematical Sciences; History of Science;
• 出版者：Springer Milan
• ISSN：2281-5937
• 卷排序：4

文摘

The article describes the machines proposed by Ibn Sahl, who lived in the tenth century, to draw continuously the three irreducible conics. These machines are based on the use of a director circle which, just as the directrix of a parabola allows one to draw the conic as a locus, and to find the tangent line at each point. All this is demonstrated with a touchscreen: the visitor may choose a conic and start several animations which show the geometry of the conic and its envelope. The corresponding machine is operated by the visitor who, by moving an on-screen pencil with their finger, can draw the conic, simulating the actual working of the machine.