Question

Na matriz B = (bij)3x3, onde bij = 5i - 2j, o valor de 2.b21 é:

Answer 1

[b11 b12 b13]
[b21 b22 b23]
[b31 b33 b33]

bij= 5i-2j
b11= 5.1-2.1= 5-2= 3
b12= 5.1-2.2= 5-4= 1
b13= 5.1-2.3= 5-6= -1
b21= 5.2-2.1= 10-2= 8
b22= 5.2-2.2= 10-4= 6
b23= 5.2-2.3= 10-6= 4
b31= 5.3-2.1= 15-2= 13
b32= 5.3-2.2= 15-4= 11
b33= 5.3-2.3= 15-6= 9

matriz pronta

[3 1 -1]
[8 6 4]
[13 11 9]

agora, o exercício pede o valor de 2.b21

temos que

b21= 8

então

2.b21= 2.8= 16