OK, notice we have two inexact differentials and exact differentials. This is a condition.

好，注意到这里面有两个不准确微分量,和一个准确微分量，这是结论。

麻省理工公开课 - 热力学与动力学课程节选

And do a little practice in manipulating these differentials.

以及掌握,如何使用它们。

麻省理工公开课 - 热力学与动力学课程节选