A matrix of the form
A = \left [ \begin{matrix} A_{11} & A_{12} \\ 0 & A_{22} \end{matrix} \right ]
is said to be block upper triangular. Assume that A_{11} is p × p, A_{22} is q × q, and A is invertible. Find a formula for A^{-1} .
A matrix of the form
A = \left [ \begin{matrix} A_{11} & A_{12} \\ 0 & A_{22} \end{matrix} \right ]
is said to be block upper triangular. Assume that A_{11} is p × p, A_{22} is q × q, and A is invertible. Find a formula for A^{-1} .