Jika a̅=i−2j+2k dan b̅=3i+6j−2k, maka hitunglah |a̅−b̅|

Jika a̅=i−2j+2k dan b̅=3i+6j−2k, maka hitunglah |a̅−b̅|

Jawabannya adalah 2√21

Jika diketahui :
u = [(u₁) (u₂) (u₃)]
v = [(v₁) (v₂) (v₃) ]
u ± v = [(u₁) (u₂)(u₃)] ± [(v₁)(v₂)(v₃)] = [(u₁±v₁) (u₂±v₂) (u₃±v₃)]
|v| = √( v₁² + v₂² + v₃²)

Diketahui :
a̅=i−2j+2k = [(1) (-2) (2)]
b̅=3i+6j−2k = [(3) (6) (-2)]

a̅−b̅ = [(1) (-2) (2)] – [(3) (6) (-2)]
= [(1-3) (-2-6) (2-(-2))]
= [(-2) (-8) (2+2)]
= [(-2) (-8) (4)]
|a̅−b̅| = √((-2)²+(-8)²+4²)
= √(4+64+16)
= √84
= √(4·21)
= √4√21
= 2√21

Jadi diperoleh nilai |a̅−b̅| = 2√21