**Question 1**

For the AR(3) process,

xt = 0.6xt−1 − 0.4xt−2 + 0.4xt−3

find the values of the autocovariance function γ(1) and γ(2)

**Question 2**

For the AR(3) model from the previous question, what is the value of the partial autocorrelation function pi(4) and why?