[tex]\Large\boxed{\begin{array}{l}\sf B=(b_{ij})_{2\times2},tal~que~b_{ij}=\begin{cases}\sf\dfrac{4i-j}{3},se~i\leqslant j\\\sf i+j,se~i>j\end{cases}\\\sf B=\begin{bmatrix}\sf a_{11}&\sf a_{12}\\\sf a_{21}&\sf a_{22}\end{bmatrix}\\\\\sf b_{11}=\dfrac{4\cdot1-1}{3}=1\\\\\sf b_{12}=\dfrac{4\cdot1-2}{3}=\dfrac{2}{3}\\\\\sf a_{21}=2+1=3\\\sf a_{22}=2+2=4\\\\\sf B=\begin{bmatrix}\sf1&\sf\dfrac{2}{3}\\\\\sf3&\sf4\end{bmatrix}\end{array}}[/tex]
