A time series {Xt} consists of two independent random white noise processes, Xt = 2wt + wt1 + nt (independent means wt and nt uncorrelated for any related time shift, i.e., Cov(ws, nt) = 0 for all s, t), where the white noise wt and nt both have the same mean 0 and variance 3. Calculate the cross-correlation function w,x(h) between {wt} and {Xt}, where h is the relative time shift