HP 49g Graphing Calculator - Manual (Page 170)

PREVAL
Type: Function
Description: With respect to the current default variable, returns the
difference between the values of a fimction at two
specified values of the variable.
PREVAL can be used in conjunction with INTVX to
evaluate definite integrals. See the example below.
Access: Calculus, 0(® DERIV. & INTEG.
Input: Level 3/Ai'gument 1: A fimction.
Level 2/Argument 2: The lower boimd.
Level 3/Argiunent 1: The upper boimd.
The bounds can be expressions.
Output: The result of the evaluation.
Flags: Exact mode must be set (flag -105 clear).
Nmneric mode must not be set (flag -03 clear).
Example: Evaluate the following;
r ^
1
(x' + 3x)dx
Command:
P R E V A L ( I N T V X ( X " 3 + 3 * X ) , 0 , 3 )
Result: 1 3 5 / 4
PREVPRIME
Type: Function
Description: Given an integer, finds the closest prime number smaller
than the integer.
Access: Arithmetic, 0@TH) INTEGER
Input: An integer.
Output: The closest prime number smaller than the integer.
Flags: Exact mode must be set (flag -105 clear).
Numeric mode must not be set (flag -03 clear).
Example: Find the closest, smaller prime number to 145.
Command:
P R E V P R I M E ( 1 4 5 )
Result:
1 3 9
Computer Algebra Commands Page 14-47