====== 2020-02-14, Friday ======

We will follow Chapter 13 in Boas. After introducing some most important equations:  heat equation, wave equation, Schroedinger equation, Laplace equation, we will do an exercise on separation of variable. 

Questions to ponder: 
  - Where does these equation comes from? 
  - Why Laplacian is everywhere? 
  - Can you write down an equation that describe the heat propagation on a surface? 
  - Or maybe wave propagation on a 'curved spacetime' (Minkowski metric tensor), say a  [[https://en.wikipedia.org/wiki/Schwarzschild_metric | Schwrazschild blackhole]]?