5.3.1. Suppose X(t), Y (t), Z(t), and W(t) are such that µX(t) = 2. RX(t1, t2) =  (a) Determine RX(t + τ, t), RY (t + τ, t), RZ(t + τ, t), and RW (t + τ, t). (b) Determine whether (i) X(t), (ii) Y (t), (iii) Z(t), and (iv) W(t) is WSS and give a reason in each case. (c) Determine RX,Y (t + τ, t), RX,Z(t + τ, t), and RX,W (t + τ, t). (d) Determine whether (i) X(t) and Y (t), (ii) X(t) and Z(t), and (iii) X(t) and W(t) are jointly WSS and give a reason in each case.