Consider the AR(2) (1+ B)X; = Zt. where Xo = X1 = 0 and t = 1,2, 3, .... (i) Is Xt stationary? Why? (ii) Find Cov(Xs, Xt) for a given nonnegative integers s and t. (iii) Simulate this process when Zt ~ N(0, 0.04) and provide basic statistics summary for this process (Let n = 200). I am adding a short do loop in R for simplicity. > x=rep (0,200) > for(i in 3:200){ + x[i]=-x [i-2] +rnorm(1,0,0.2)}