PLEASE GIVE DETAILED, STEP BY STEP ANSWER. IF YOU DO$,$ I WILL UPVOTE. For MA$(1)$ model $x_t=w_{t-1}+w_t,$ using the innovation algorithm to show that

${}_{n1}=\frac{{}^2}{P_n^{n-1}},{}_{nj}=0,j=2,3,$cdots,$n$