Question

Determine a soma dos elementos da 3ª coluna da matriz A = (aij)3x3 tal que aij = 4 + 2i –j. *
10 pontos
21
15
18
24

Answer 1

$\large\boxed{\begin{array}{l}\underline{\rm Elementos~da~3^a~coluna~da~matriz~A}\\\sf a_{13}~~a_{23}~e~a_{33}\\\sf a_{13}=4+2\cdot1-3=4+2-3=3\\\sf a_{23}=4+2\cdot2-3=4+4-3=5\\\sf a_{33}=4+2\cdot3-3=4+6-3=7\\\sf a_{13}+a_{23}+a_{33}=3+5+7=15\end{array}}$