Key Equations

Key Equations

Identity matrix for a matrix	$I_2=\left[\begin{array}{cc}1& 0\\ 0& 1\end{array}\right]$
Identity matrix for a matrix	$I_3=\left[\begin{array}{ccc}1& 0& 0\\ 0& 1& 0\\ 0& 0& 1\end{array}\right]$
Multiplicative inverse of a matrix	$A^{\mathrm{-1}}=\frac{1}{ad-bc}\left[\begin{array}{cc}d& -b\\ -c& a\end{array}\right],\text{where }ad-bc\ne 0$