- #1
jesuslovesu
- 198
- 0
Homework Statement
A = [tex]
\left| \begin{array}{ccc}
2 & 0 & 4 \\
0 & 4 & -8 \\
3 & -1 & 2 \end{array} \right|.\]
[/tex]
Find the LU decomposition.
The Attempt at a Solution
My question is why do you need to interchange rows 3 & 1 at the start of the problem? My initial attempt was to find the upper matrix using the format as given. I got
U = [tex]
\left| \begin{array}{ccc}
2 & 0 & 4 \\
0 & 4 & -8 \\
0 & 0 & -6 \end{array} \right|.\]
[/tex]
doesn't that satisfy the requirements for an U matrix?
According to the calculator I'm using the U matrix should be
[tex]
\left| \begin{array}{ccc}
3 & -1 & 2 \\
0 & 4 & -8 \\
0 & 0 & 4 \end{array} \right|.\]
[/tex]