- #1
Philosophaie
- 462
- 0
I need to find the adj(A) for a 4x4 Matrix.
[tex]A = \begin{array} a11 & a12 & a13 & a14 \\ a21 & a22 & a23 & a24 \\ a31 & a32 & a33 & a34 \\ a41 & a42 & a43 & a44 \end{array}[/tex]
I have tried:
[tex]adj(A_{ij}) = (-1)^{i+j}*A_{ji}[/tex]
but I get the wrong answer for the inverse:
[tex]A^{-1} = \frac{adj(A)}{det(A)}[/tex]
and this does not work:
[tex]A*A^{-1} = I[/tex]
where
[tex]I= \begin{array} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & 1 \end{array}[/tex]
[tex]A = \begin{array} a11 & a12 & a13 & a14 \\ a21 & a22 & a23 & a24 \\ a31 & a32 & a33 & a34 \\ a41 & a42 & a43 & a44 \end{array}[/tex]
I have tried:
[tex]adj(A_{ij}) = (-1)^{i+j}*A_{ji}[/tex]
but I get the wrong answer for the inverse:
[tex]A^{-1} = \frac{adj(A)}{det(A)}[/tex]
and this does not work:
[tex]A*A^{-1} = I[/tex]
where
[tex]I= \begin{array} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & 1 \end{array}[/tex]