In several places and for different purposes, Ibn al-Haytham has studied the variations of a well-known function. The context of these applications reveals some characteristics of Ibn al-Haytham's mathematical and physical thought. An in-depth study of his mathematical proofs of monotony show how close he was from an elaborate concept of the continuous.

中文翻译：

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UN LEMME D'ANALYSE 不要使用 IBN AL-HAYTHAM EN GNOMONIQUE, DIOPTRIQUE ET CINÉMATIQUE CÉLESTE

Ibn al-Haytham 在多个地方出于不同的目的研究了一个著名函数的变体。这些应用的背景揭示了伊本·海瑟姆数学和物理思想的一些特征。对他关于单调性的数学证明的深入研究表明，他离一个详尽的连续概念有多近。