Question

Calcule a matriz inversa da matriz M= [3 1 3 2]

Answer 1

$\Large\boxed{\begin{array}{l}\sf M=\begin{bmatrix}\sf3&\sf1\\\sf3&\sf2\end{bmatrix}\\\sf det\,M=3\cdot2-1\cdot 3=6-3=3\\\\\sf cof\,M=\begin{bmatrix}\sf2&\sf-3\\\sf-1&\sf3\end{bmatrix}\\\\\sf adj\,M=(cof\,M)^T\\\\\sf adj\,M=\begin{bmatrix}\sf2&\sf-1\\\sf-3&\sf3\end{bmatrix}\\\\\sf M^{-1}=\dfrac{1}{det\,M}\cdot adj\,M\\\\\sf M^{-1}=\dfrac{1}{3}\cdot\begin{bmatrix}\sf2&\sf-1\\\sf-3&\sf3\end{bmatrix}\\\huge\boxed{\boxed{\boxed{\boxed{\sf\red{\maltese}\blue{~alternativa~e}}}}}\end{array}}$