Update src/6_eigenvectors_QM.md

src/6_eigenvectors_QM.md

@@ -100,12 +100,12 @@ $$
 &  A_{23} \\ A_{31}  &  A_{32}
 &  A_{33}  \end{array} \right| = 
 \begin{array}{c} 
-A_{11} \left|  \begin{array}{cc} A_{22}  & A_{23} \\ A_{32}  &  A_{33} \end{array} \right| \\
++ A_{11} \left|  \begin{array}{cc} A_{22}  & A_{23} \\ A_{32}  &  A_{33} \end{array} \right| \\
 - A_{12} \left|  \begin{array}{cc} A_{21}  & A_{23} \\ A_{31}  &  A_{33} \end{array} \right| \\
 + A_{13} \left|  \begin{array}{cc} A_{21}  & A_{22} \\ A_{31}  &  A_{32} \end{array} \right|
 \end{array}
 $$
-"
+
 !!! check "Example":
     Let us illustrate how to compute eigenvalues and eigenvectors by considering a $n=2$ vector space. Consider the following matrix
     $$