Show by example that the random process Z (t) = X (t) + Y (t) may be a wide sense stationary process even though the random processes X (t) and Y (t) are not.Let and be independent, wide sense stationary random processes with zero- means and identical autocorrelation functions. Then let X (t) = A (t) sin (t) Y (t) = B (t) cos (t) and Show that X (t) and Y (t) are not wide sense stationary. Then show that Z (t) is wide sense stationary.