Let us assume that θ ∈ (-1, +1) is known, that {Wt} is a Gaussian white noise with variance one, and that
is a Gaussian white noise with variance θ2. Show that the MA(1) time series {Xt}t defined by:

Show that the MA(1) time series {Xt}t defined by:

have the same auto-covariance functions. Do they have the same auto-correlation functions?