To “divide” an array by a square matrix, To use a matrix element in an algebraic expression – HP 48g Graphing Calculator User Manual

Page 176

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To “divide” an array by a square matrix:

1. Enter the array onto the stack.

2. Enter the square matrix. The number of rows in the matrix must

equal the number of rows in the array (elements in the vector).

3. Press © to calculate Y-X E The result will be a vector of the

same size as the original. Note that array division can produce

erroneous results if you are using ill-conditioned matrices. See

“Ill-Conditioned and Singular Matrices” on page 14-16 .

Using Arrays and Array Elements in Algebraic
Expressions

You can perform calculations with array elements using algebraic

syntax. The array must be represented by a name in the symbolic

expression or equation.

To use a

matrix element in

an algebraic expression:

1. Make sure that the array is stored in a named variable.

2. Create the algebraic expression and, at the point where the matrix

element is to be used, type the array name and press S)0'

3. Enter the subscripts for the element:

■ For a vector, enter one subscript (position number of the

element).

■ For a matrix, enter two subscripts separated by SDO (row and

column numbers of the element).

Example: Enter a symbolic expression for the sum of all elements of

a 2

5 matrix stored in MATR.

Step 1:

Begin the expression.

r^f EQUATION)

® 5 (Q

14-12 Matrices and Linear Algebra

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