# Subtmod; Sylvester - HP 48gII Advanced User's Reference Manual

Graphing calculator.

Description:
Substitutes a value for a variable in an expression. The value can be numeric or an expression.
This is similar to the Where function, denoted by the symbol |, but SUBST substitutes
without evaluating the resulting expression.
Algebra, ...×L, P
Access:
Input:
Level 2/Argument 1: An expression.
Level 1/Argument 2: The value or expression to be substituted.
Output:
The expression with the substitution made.
Flags:
Exact mode must be set (flag –105 clear).
Numeric mode must not be set (flag -3 clear).
Radians mode must be set (flag –17 set).
Example:
Substitute x = z+1 for x in the following expression, and apply the EXPAND command to
simplify the result:
2
x
+
3x
+
Command:
SUBST(X^2+3*X+7,X=Z+1)
EXPAND(ANS(1))
Result:
Z^2+5*Z+11
| (where command)

## SUBTMOD

Type:
Function
Description:
Performs a subtraction, modulo the current modulus.
Arithmetic, !Þ
Access:
Input:
Level 2/Argument 1: The object or number to be subtracted from.
Level 1/Argument 2: The object or number to subtract.
Output:
The result of the subtraction, modulo the current modulus.
Flags:
Exact mode must be set (flag –105 clear).
Numeric mode must not be set (flag -3 clear).
Radians mode must be set (flag –17 set).

### SYLVESTER

Type:
Command
Description:
For a symmetric matrix A, returns D and P where D is a diagonal matrix and
A = P
DP
T
Access:
Input:
A symmetric matrix.
Output:
Level 2/Item 1: the diagonal matrix, D.
Level 1/Item 2: The matrix P.
Flags:
Exact mode must be set (flag –105 clear).
Numeric mode must not be set (flag -3 clear).
Radians mode must be set (flag –17 set).
Example:
Rewrite in P
1 2
2 4
Command:
SYLVESTER([1, 2][2, 4])
4-70 Computer Algebra Commands
ALG
7
L
MODULO
DP form the matrix:
T