In the geometry of curves, an isoptic is the set of points for which two tangents of a given curve meet at a given angle. The orthoptic is the isoptic whose given angle is a right angle.
英汉双解词典包含3185865条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。