I could change my external pressure through the whole process, and that's the path.

事实上外界压强,也不必固定。

麻省理工公开课 - 热力学与动力学课程节选

It's nR log of p2 over p1 for the process where there's a pressure change.

结果是dS等于nR乘以p2除以p1的对数,这是对压强变化的结果。

麻省理工公开课 - 热力学与动力学课程节选