Question

Dada a matriz A = [aij]1x3, sendo aij=3i - j e B=[bij] 3x1, com bij = 2i + j, calcule A x B: 

A) [10]
B) [11]
C) [12]
D) [9 10]
E) [11 12] ​

Answer 1

A = [a11 a12 a13]

aij = 3i - j

a11 = 3 . 1 - 1 = 3 - 1 = 2

aij = 3i - j

a12 = 3 . 1 - 2 = 3 - 2 = 1

aij = 3i - j

a13 = 3 . 1 - 3 = 3 - 3 = 0

A = [2 1 0]

B = [b11]

[b21]

[b31]

bij = 2i + j

b11 = 2 . 1 + 1 = 2 + 1 = 3

bij = 2i + j

b21 = 2 . 2 + 1 = 4 + 1 = 5

bij = 2i + j

b31 = 2 . 3 + 1 = 6 + 1 = 7

B = [3]

[5]

[7]

A × B = (2 . 3) + (1 . 5) + (0 . 7)

A × B = 6 + 5 + 0

A × B = 11

Letra B