Well, however we settle that issue, notice there's still one other assumption that all these positions still have in common.

不管我们如何解决这个问题，我们都会发现有一个假定,是这些观点都共有的。

耶鲁公开课 - 死亡课程节选

Now, I want to do one concrete problem where you will see how to use these derivatives.

现在我要解决一个具体的问题,从中你会明白如何运用这些导数

耶鲁公开课 - 基础物理课程节选