Reference Guide

Full Command and Function Reference 3-223
G(x + 1) – G(x) = f(x)
where x is the specified variable.
Access: !Ö DERIV L
Input: Level 2/Argument 1: A function
Level 1/Argument 2: The variable to calculate the antiderivative with respect to.
Output: The discrete antiderivative of the function.
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: Obtain the discrete antiderivative with respect to the variable y of the expression:
2x-2y
Command: SIGMA(2*X-2*Y,Y)
Result: -(Y^2 –(2*X+1)*Y)
See also: SIGMAVX, RISCH
SIGMAVX
Type: Function
Description: Calculates the discrete antiderivative of a function f with respect to the current variable. This is a
function G such that:
G(x + 1) – G(x) = f(x)
where x is the current variable.
Access: !Ö DERIV LL
Input: Level 1/Argument 1: A function.
Output: The discrete antiderivative of the function.
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: Obtain the discrete antiderivative with respect to the current variable x of the expression:
2x-2y
Command: SIGMAVX(2*X-2*Y)
Result: X^2 –(2*Y+1)*X
See also: SIGMA, RISCH
SIGN
Type: Function
Description: Sign Function: Returns the sign of a real number argument, the sign of the numerical part of a
unit object argument, or the unit vector in the direction of a complex number argument.
For real number and unit object arguments, the sign is defined as +1 for positive arguments, –1
for negative arguments. In exact mode, the sign for argument 0 is undefined (?). In approximate
mode, the sign for argument 0 is 0. SIGN in the !´ menu returns the sign of a number, while
SIGN in the …ß menu returns the unit vector of a complex number.
For a complex argument:
SIGN x iy+( )
x
x
2
y
2
+
---------------------
i
y
x
2
y
2
+
---------------------+=