Time-Invariant System Definition
A time invariant system is a system that produces equivalent results for the following cases:
1. A time shifted input $ x(t+t_0) \, $ is entered into the system.
2. An input $ x(t) \, $ is entered into the system then time shifted by $ t_0 \, $.
Time-Invariant System
Consider the system: $ y(t)=x(t-3) \, $
If $ x(t) \, $ is first time shifted, then put into the system:
$ x(t) \longarrow x(t-t_0) \longarrow y(t)=(t-3-t_0)\, $
