This is going to be probably a homework at some point to do this. For now, let's take it for granted. Let's take it for granted that we know how to calculate this derivative from an equation of state like this.

这可能是将来的一个课后作业,现在，请把这当成理所当然的，理所当然地认为我们,知道怎样从一个状态,方程计算这样的微分式。

麻省理工公开课 - 热力学与动力学课程节选

We can measure the heat capacity at constant volume, and now we have another term, and if we can figure out how to measure it, we'll have a complete form for this differential du which will enable us to calculate du for any process.

我们能够测量恒定体积下的热容，这里我们有另一项，如果能够知道怎么测量它，问我们就有了这个完整的微分式,就能够对任何过程计算。

麻省理工公开课 - 热力学与动力学课程节选