146 Section 12: Calculating with Matrices

Using R0 and R1. To access a particular matrix element, store its row number in R0 and its column number in R1. These numbers won't change automatically (unless the calculator is in User mode).

∙To recall the element value (after storing the row and column numbers), press l followed by the letter key specifying the matrix.

∙To store a value in that element (after storing the row and column numbers), place the value in the X-register and press O followed by the letter key specifying the matrix.

Example: Store the value 9 as the element in row 2, column 3 of matrix A from the previous example.

Keystrokes

Display

 

2 O0

2.0000

3 O1

3.0000

9

9

 

OA

A

2,3

 

9.0000

Stores row number in R0. Stores column number in R1.

Keys the new element value into the X-register.

Row 2, column 3 of A. Value of a23.

Using the Stack. You can use the stack registers to specify a particular matrix element. This eliminates the need to change the numbers in R0 and R1.

∙To recall an element value, enter the row number and column number into the stack (in that order). Then press l followed by the letter key specifying the matrix. The element value is placed in the X-register. (The row and column numbers are lost from the stack.)

∙To store an element value, first enter the value into the stack followed by the row number and column number. Then press O followed by the letter key specifying the matrix. (The row and column numbers are lost from the stack; the element value is returned to the X-register.)

Note that these are the only operations in which the blue key precedes a gold letter key.