Question

Dadas as matrizes A= $\left[\begin{array}{ccc}1&4&0\\1&-3&1\end{array}\right]$ e B = $\left[\begin{array}{ccc}1&-1\\-1&1\\5&0\end{array}\right]$ , Calcule :

a) A.B

b)B.A

Answer 1

a11=1-4+0=-3
a12=-1+4+0=3
a21=1+4+5=10
a22=-1-3+0=-4
Logo
$A.B= \left[\begin{array}{cc}-3&3\\10&-4\\\end{array}\right]$

a11=1-1=0
a12=4+3=7
a13=0-1=-1
a21=-1+1=0
a22=-4-3=-7
a23=0+1=1
a31=5
a32=20
a33=0
$B.A´= \left[\begin{array}{ccc}0&7&-1\\0&-7&1\\5&20&0\end{array}\right]$