Signals and Systems - Engineering

Q1:

Which one of the systems described by the following I/P - O/P relations is time invariant

A y(n) = n x(n)

B y(n) = x(n) - x(n - 1)

C y(n) = x(- n)

D
y(n) = x(n) cos 2pf0n

ANS:B - y(n) = x(n) - x(n - 1)

No answer description is available.