HP 48gII - Manual (Page 312)

Page 10-12
want to extract elements a
12
, a
13
, a
22
, and a
23
from the last result, as a 2 ×2
sub-matrix, in ALG mode, use:
In RPN mode, assuming that the original 2
×3 matrix is already in the stack,
use {1,2} ` {2,3} ` SUB.
Function REPL
Function REPL replaces or inserts a sub-matrix into a larger one. The input for
this function is the matrix where the replacement will take place, the location
where the replacement begins, and the matrix to be inserted. For example,
keeping the matrix that we inherited from the previous example, enter the
matrix:
[[1,2,3],[4,5,6],[7,8,9]] . In ALG mode, the following
screen shot to the left shows the new matrix before pressing `. The screen
shot to the right shows the application of function RPL to replace the matrix in
ANS(2), the 2×2 matrix, into the 3×3 matrix currently located in ANS(1),
starting at position
{2,2}:
If working in the RPN mode, assuming that the 2
×2 matrix was originally in
the stack, we proceed as follows:
[[1,2,3],[4,5,6],[7,8,9]]`™ (this last key swaps the
contents of stack levels 1 and 2)
{1,2} ` ™ (another swapping of
levels 1 and 2) REPL.