deletions | additions       diff --git a/Complex.tex b/Complex.tex  index 190313a..dcfec50 100644  --- a/Complex.tex  +++ b/Complex.tex 
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\begin{bmatrix}a \\ b \\ c \\ d \end{bmatrix}=\frac{1}{eg+fh}\begin{bmatrix}g&h&0&0\\0&0&-h&g\\0&0&e&f\\-f&e&0&0\end{bmatrix}  \begin{bmatrix}1 \\ 0 \\ 0 \\ 1 \end{bmatrix}=\frac{1}{eg+fh}\begin{bmatrix}g\\g\\f\\-f\end{bmatrix}\end{equation}  %This This  gives the general formula for the 'cross inverse' of a 2 by 2 matrix as \begin{equation} %\begin{bmatrix} a&b\\c&d\end{bmatrix}^{-1}=\frac{1}{ac+bd}\begin{bmatrix}c & -d \\ \mat{a}{b}{c}{d}^{-1}=\frac{1}{ac+bd}\mat{c}{c}{b}{-b}  \end{equation}  Which is very curious as it only relies on all of the elements weakly in the form of  a & -b \end{bmatrix}  %\end{equation} coefficient.