Reference Guide

Full Command and Function Reference 3-91
FOURIER
Type: Function
Description: Returns the n
th
coefficient of a complex Fourier series expansion. The PERIOD variable must be in
the CAS directory, CASDIR, or in current path, and set to hold L, the period of the input
function. The expression is expanded in terms of the current CAS variable.
Access: Calculus !Ö DERIV . & INTEG .
Input: Level 1/Argument 2: An expression in terms of the current variable
Level 2/Argument 1: The number, n, of the coefficient to return.
Output: The nth Fourier coefficient of the expression.
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).
Complex mode must be set, that is, flag –103 must be set.
Example: Obtain the Fourier coefficient as below, with the default value of 2π in the PERIOD variable in
CASDIR, and simplify it with EXPAND :
Command: FOURIER(X^2,0)
EXPAND(ANS(1))
Result: 4/3* π ^2
FP
Type: Function
Description: Fractional Part Function: Returns the fractional part of the argument.
The result has the same sign as the argument.
Access: !´ REAL L FP ( ´ is the left-shift of the Pkey).
Flags: Numerical Results (–3)
Input/Output:
Level 1/Argument 1 Level 1/Item 1
x
→
y
x_unit
→
y_unit
'
symb
'
→
'
FP(symb)
'
Example 1: -32.3 FP returns -.3 .
Example 2: 32.3_m FP returns .3_m .
See also: IP
FREE
Type: Command
Description: Do not use this command, a carry-over from the HP 48SX for handling plug-in RAM cards.
Access: …µ FREE
FREEZE
Type: Command
Description: Freeze Display Command: Freezes the part of the display specified by n
display area
, so that it is not
updated until a key is pressed.
Normally, the stack display is updated as soon as the calculator is ready for data input. For
example, when HALT stops a running program, or when a program ends, any displayed messages
are cleared. The FREEZE command “freezes” a part or all of the display so that it is not updated
until a key is pressed. This allows, for example, a prompting message to persist after a program
halts to await data input.
n
display area
is the sum of the value codes for the areas to be frozen: