Consider the causal LTI system described by the following: y[n] = 1/3 (x[n] + x [n – 1] + x[n – 2]) Determine the impulse response of the system. Is the system stable? Is it causal? Justify your answer. Determine the frequency response of the system. An input x[n] = 1 + cos (pi/2 n + pi/3) + 2cos(pi n + pi) is applied to the system. Determine the corresponding steady-state response y[n].