HP 39g Graphing Calculator - Manual (Page 149)

Loop functions
ITERATE
RECURSE
The loop functions display a result after evaluating an
expression a given number of times.
Repeatedly for Mines evaluates an expression in terms of
variable. The value for variable is updated each time, starting
with initialvalue.
ITERATE {expression, variable, initialvalue,
#times)
Example
ITERATE ( X ^ , X , 2 , 3 ) returns 2 56
Provides a method of defining a sequence without using the
Symbolic view of the Sequence aplet. If used with I (“where”),
RECURSE will step through the evaluation.
RECURSE (sequencename, term-n, term! , term2)
Example
R E C U R S E ( U , U ( N - 1 ) * N , 1 , 2 ) H f f l 3 u l ( N )
Stores a factorial-calculating function named UI.
When you enter Ul ( 5), for example, the function
calculates 5 ! (12 0).
Summation. Finds the sum of expression with respect to
variable from initialvalue to finalvalue.
5) {variable=imtialvalue, finalvalue, expression)
Example
S ( C = 1 , 5 , c 2 ) returns 55.
Matrix functions
These functions are for matrix data stored in matrix variables.
See “Matrix functions and commands” on page 12-9.
Using mathematical functions 10-11