bila IaI = 4 IbI = 6 dan a . (a+b)= 28, maka sudut antara vektor a dan b adalah

Mapel : Matematika
Kelas : XII SMA
Bab : Vektor

Diketahui :
|a| = 4
|b| = 6
a . (a + b) = 28

Ditanya : 
β = ... °

Dijawab : 
Ingat sifat Perkalian Skalar Dua Vektor

[tex]a(a + b) = a.a + a.b \\ 28 = a . a + a.b \\ 28 = |a|^2 + |a| |b| cos \beta \\ 28 = 4^2 + (4)(6)cos \beta \\ 28 = 16 + 24cos \beta \\ 24cos \beta = 28 - 16 \\ 24cos \beta = 12 \\ cos \beta = \frac{12}{24} \\ cos \beta = \frac{1}{2} \\ cos \beta = cos 60^o \\ \beta = 60^o [/tex]


By : [tex]MIPAStudyCenterID[/tex]