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| | Cryptography |
 | | To compute the determinant of a 2 x 2 matrix, step across the entries in the first row of the matrix, multiply each entry by the determinant of the 1 x 1 matrix that appears when the row and the column the entry appears in are eliminated from the matrix. |
 | | The determinant of a 3 x 3 matrix is produced in the same way: step across the first row, multiply each entry by the determinant of the 2 x 2 matrix that appears when the entry's row and column are crossed out, and alternately add and subtract the resulting numbers. |
 | | Next, the matrix is flipped over the diagonal from the upper left corner to the lower right corner so that the first row be comes the first column, the second rows becomes the second column, and so on. |
| www.threaded.com /cryptography8.htm (13300 words) |
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