Question

Diketahui |a| = akar 6 . (a-b)(a+b) = 0 , dan a(a-b) = 3 . besar sudutnantar vektor a dan b adalah ...

Answer 1

Materi Vektor
Kelas X
Kata Kunci : Dot Product

|a| = akar 6

(a-b).(a+b) = 0
a.a - b.b  = 0
|a|.|a| - |b|.|b| = 0
√6.√6 - |b|² = 0
|b| = √6

a(a-b) = 3
a.a - a.b = 3
|a|.|a| - |a|.|b|.cos α = 3
6 - √6.√6.cosα = 3
6 cosα = 3
cos α = 1/2
α = arc cos (1/2)
α = 60°