HP 48gII - Manual (Page 326)

Page 10-26
This same exercise done in RPN mode is shown in the next figure. The left-
hand side figure shows the setting up of the matrix, the factor and the row
number, in stack levels 3, 2, and 1. The right-hand side figure shows the
resulting matrix after function RCI is activated.
Function RCIJ
Function RCIJ stands for “take Row I and multiplying it by a constant C and
then add that multiplied row to row J, replacing row J with the resulting sum.”
This type of row operation is very common in the process of Gaussian or
Gauss-Jordan elimination (more details on this procedure are presented in a
subsequent Chapter). The arguments of the function are: (1) the matrix, (2)
the constant value, (3) the row to be multiplied by the constant in(2), and (4)
the row to be replaced by the resulting sum as described above. For example,
taking the matrix stored in variable A, we are going to multiply column 3
times 1.5, and add it to column 2. The following example is performed in
ALG mode:
In RPN mode, enter the matrix first, followed by the constant value, then by
the row to be multiplied by the constant value, and finally enter the row that
will be replaced. The following figure shows the RPN stack before and after
applying function RCIJ under the same conditions as in the ALG example
shown above: