Part D : Time Invariance
A time invariant system is a system that commutes a time delay by to, for any to.
example : x(t) ----->SYSTEM-----> y(t)= 10 x(t) proof : (i) x(t)----> TIME DELAY------>y(t) =x(t-to)------->SYSTEM----> z(t) = 10y(t)=10x(t-to) x(t)-----> SYSTEM----->y(t) = 10 x(t)---> TIME DELAY-----> z(t)= y(t-to)=10 x (t-to) Since both outputs are same,the system is time invariant.