HP 39gs_40gs_Mastering The Graphing Calculator_English_E_F2224-90010

ROWNORM(<matrix>)
Finds the row norm of a matrix: the maximum, over all rows contained
in the matrix, of the absolute values of the sum of the elements in each
row.
⎡
123
⎤
⎢
=
Eg. For the matrix
M
1 456
⎥
⎥
, the row with the largest absolute sum of 15 is row 2.
⎢
⎢
−
154
⎥
⎦ ⎣
RREF(<matrix>)
This function takes an augmented matrix of size n by n+1 and transforms it into reduced row echelon form,
with the final column containing the solution.
−
2 314
⎫
x y z
=
+
⎪
Eg. The system of equations
2
xyz
+−=−
3
⎬
42 214
⎭
x y z
=
− +
⎪
⎡
1 23
−
14
⎤
is written as the augmented matrix
⎢
⎢
21 1
−
−
3
⎥
⎥
⎢
4 22
⎣
−
14
⎥
⎦
which is then stored as a 3x4 real matrix
M1.
We now use the function
RREF to change this to reduced row echelon
form and store it as
M2.
This gives the final result shown in the matrix
M2 on the right, giving a
solution of (1, -2, 3).
The huge advantage of this function is that it allows for inconsistent
matrices which can’t be solved by an inverse matrix.
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