diketahui a (2,3,1) b (4,2,2) c (3,4,3) ditanya sudut antara ab dan ac

VEKTOR

AB = c
c= B - A
= (2,-1,1)
IcI = V6

AC = b
b = C - A
= (1,1,2)
IbI = V6

Maka
b.c = lbllclcosθ
cos θ = 1(2)+1(-1)+2(1) / (V6)^2
= 4-1 / 6
= 3/6 = 1/2
arc cos 1/2 = 60°