a= (2, 1, -3) dan b= (-1, 3, -2)
ab = -2 + 3 + 6 = 7│a│ = √(2²+1²+(-3)²) = √14│b│ = √(-1²+3²+(-2)²) = √14
cos α = ab/│a││b│ = 7/(√14√14)
= 7/14 = 1/2α = 60°
ab = -2 + 3 + 6 = 7│a│ = √(2²+1²+(-3)²) = √14│b│ = √(-1²+3²+(-2)²) = √14
cos α = ab/│a││b│ = 7/(√14√14)
= 7/14 = 1/2α = 60°
Jika A = ( 4,5,6) dan B = (7,8,9) maka A X B ?
a. 3i + 6j + 3k e. 1i + 1j + 1k
b. 2i + 5j + 2k
c. 1i + 2j + 3k
d. 2i + 2j+ 2k
jawab :
Det :
= ( 5×9 – 8×6 ) I – ( 4×9 – 7×6 ) j + ( 4×8 – 7×5)k
= -3i + 6j – 3k
Jawabannya : A
SUMBER:
