And so I'm going to go back to this idea of a class, and let's build the first of these, and that is shown right here on this piece of your handout.

你把半径加到一起,你不会把角度加到一起，你需要再笛卡尔坐标下，进行这个操作,那么我这里在讲的就是。

麻省理工公开课 - 计算机科学及编程导论课程节选