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

Um-hmm. So, it's going to be the y z nodal plane, or in other words, we can say it's any place where phi is equal to 90 degrees.

嗯，是ｙｚ平面，换句话说，是在phi等于９０度的面。

麻省理工公开课 - 化学原理课程节选

Then, I gave you one other very important example of a particle moving in the x-y plane.

下面我再拿一个重要的例子,质点在 x-y 平面内的运动

耶鲁公开课 - 基础物理课程节选

Our picture now is going to be some particle that's traveling in the x-y plane.

我们现在的情景是在 x-y 平面内,运动的质点

耶鲁公开课 - 基础物理课程节选

And that's the following. Let's take a particle that is moving in the x-y plane, so that at one instance-- sorry, let me change this graph-- is here--oh, this is bad.

接下来,我们来看一个物体,在 x-y 平面内运动,在这个例子中,对不起,我要重画一下这个图,在这里,这画得不好

耶鲁公开课 - 基础物理课程节选