Another way to represent a point in a plane is I've got a radius and I've got an angle from the x-axis, right, and that's a standard thing you might do.

平面上面的点的方法,也就是极坐标,上面那种方法其实是，如果你们喜欢我这么说的话,笛卡尔坐标表示法。

麻省理工公开课 - 计算机科学及编程导论课程节选