1. The problem statement, all variables and given/known data As I know wave equation has d^2/dt^2,but Schrodinger's equation has only d/dt (Time-dependent). Why these eq has different thing(d/dt, d^2/dt^2)? I assume if Schrodinger's equation has d^2/dt^2(not d/dt), eigenfunction of Schrodinger's equation is not stable along with time. And continuity equation is also not used. But I don't know I wrong or not. 2. Relevant equations Gasiorowicz 3rd edtion(chapter 2) But this is only said analysis of probability is also changed. That's all. (I'm not sure in English edition.My book is not an English edition) 3. The attempt at a solution I'm not sure.