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学习椭圆时,我们常常研究椭圆上的点到焦点的距离(称为焦半径)问题.若在极坐标系中研究椭圆,极点通常取在椭圆的一个焦点,极径ρ即为椭圆的焦半径,因此,若用极坐标来解有关焦半径的问题,则有天然之利;但不少同学(尤其是学文科的同学)不熟悉极坐标系,若能借用极径和极角的思想,就可以很轻松地处理椭圆中与焦半径有关的问题.
When learning ellipses, we often study the point-to-focus distance (called the focal radius) problem on ellipses.If the ellipse is studied in polar coordinates, the pole is usually taken at a focal point of the ellipse, and the polar radius ρ is the focal radius of the ellipse Therefore, it is natural for polar coordinates to solve the issue of focal radius. However, many students, especially those who are liberal arts students, are unfamiliar with polar coordinate systems. If they borrow the thought of polar axes and polar angles, You can easily deal with elliptical and focal radius problems.