Question

a=(3,2,0)
b=(-1,4,2)

Найти
1) a*b
2) a x b
3) |a| , |b|
4) (a+b)

Answer 1

1)
a * b = (3·(-1) + 2·4 + 0·2) = -3 + 8 + 0 = 5
2)
a x b = (2·2 - 0·4; 0·(-1) - 3·2; 3·4 - 2·(-1)) = (4; -6; 14)
3)
$|a|= sqrt{3^2+2^2+0^2}= sqrt{13}$
4)
$|b|= sqrt{(-1)^2+4^2+2^2}= sqrt{21}$
5)
a + b = (3-1; 2+4; 0+2) = (2; 6; 2)