Find the angle between U=4i-2j+4k and V=3i-6j-2k (a)68(b)67(c)58(d)69

Answer 1

U•V = 12+12-8 = 16
|U| = √(16+4+16) = 6
|V| = √(9+36+4) = 7
so, since
U•V = |U| |V| cosθ,
cosθ = 16/42
θ = 67.61°