2+5+8+1=16
16/4=4
4 is the average (mean)
Cos(2θ) = cos²θ - sin²θ = (1-sin²θ)-sin²θ = 1-2(7/9)^2 = -17/81
1) Spend final weeks in a prison closest to their home.
2) Security reasons.
3) Inmates required to complete certain activities, and are not currently offered in their prison, so would move to another facility.
Hope I helped :)
