HP 39g+ - Manual (Page 147)

Using mathematical functions 10-11
Loop functions
The loop functions display a result after evaluating an
expression a given number of times.
ITERATE Repeatedly for #times 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 2 ,X,2,3) returns 256
RECURSE Provides a method of defining a sequence without using the
Symbolic view of the Sequence aplet. If used with | (“where”),
RECURSE will step through the evaluation.
RECURSE( sequencename , term-n , term1 , term2 )
Example
RECURSE(U,U(N-1)*N,1,2) TUPc•Ã U1(N)
Stores a factorial–calculating function named U1.
When you enter U1(5) , for example, the function
calculates 5! ( 120 ).
Σ
Summation. Finds the sum of expression with respect to
variable from initialvalue to finalvalue.
Σ
( variable = initialvalue , finalvalue , expression )
Example
Σ
(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.