Linear System Definition
A system takes a given input and produces an output. For the system to be linear it must preserve addition and multiplication. In mathematical terms:
$ x(t+t0)=x(t) + x(t0) $
and
$ x(k*t)=k*x(t) $
Linear System Example
font=4 Consider the system y(t)=I_n*x(t) where $ I^n $ is the identity matrix and y(t) and x(t) are n x 1 vectors.