v We don't know what it is yet. In order to change this from a p to a V, you have to use the chain rule. So let's use the chain rule.

为了把这里的p变成,我们需要利用链式法则,好，让我们使用链式法则。

麻省理工公开课 - 热力学与动力学课程节选

And the point is that the second derivative of A, with respect to V and T in this order is the same as the second derivative of a with respect to T and V in this order.

问题的关键在于A的二阶导数，对V和T以这样一个顺序求导,和对T和V以这样一个顺序,求导是一样的。

麻省理工公开课 - 热力学与动力学课程节选