Question

23. Dadas as matrizes A=(1 3) (0 -2) e B= (4 -1) (1 2)
determine:
a) AB
b) ВА
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Answer 1

$\sf{A\cdot B}=\begin{bmatrix}1\cdot4+3\cdot1&1\cdot(-1)+3\cdot2\\0\cdot4-2\cdot1&0\cdot(-1)-2\cdot2\end{bmatrix}$

$\sf{A\cdot B}=\begin{bmatrix}7&5\\-2&-4\end{bmatrix}$

$\sf{B\cdot A}=\begin{bmatrix}4\cdot1-1\cdot0&4\cdot3-1\cdot(-2)\\1\cdot1+2\cdot0&1\cdot3+2\cdot(-2)\end{bmatrix}$

$\sf{B\cdot A}=\begin{bmatrix}4&14\\1&-1\end{bmatrix}$