Question

A= (ay) 2×2 , tal que aij = i-j

Answer 1

Temos que:

$a_{11} = 1-1=0\\a_{12}=1-2=-1\\a_{21}=2-1=1\\a_{22}=2-2=0$

Logo sua matriz é:

$\left[\begin{array}{cc}0&-1\\1&0\end{array}\right]$