Tolong dibantu nomer 8,10 dan 11 nya

8) g = BA = a - b = (2,4,-2) - (4,1,-1) = (-2,3,-1)
=> |AB| = √((-2)^2 + 3^2 + (-1)^2) = √(4 + 9 + 1) = √14

h = CD = d - c = (8,2,-1) - (7,0,2) = (1,2,-3)
=> |CD| = √(1^2 + 2^2 + (-3)^2) = √(1 + 4 + 9) = √14
Sudut antara g dan h = ¢
Cos ¢ = (BA.CD)/|BA|.|CD| = (-2(1) + 3(2) + (-1)(-3)) / √14√14 = 7/14 = 1/2
Cos ¢ = cos 60°
¢ = 60°