HP 39g+ - Manual (Page 154)

11-10 Using mathematical functions
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
, term
1
, term
2 )
Example
RECURSE(U,U(N-1)*N,1,2) 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 13-9.
Polynomial functions
Polynomials are products of constants (coefficients) and
variables raised to powers (terms).
POLYCOEF Polynomial coefficients. Returns the coefficients of the
polynomial with the specified roots.
POLYCOEF ([roots])
Example
To find the polynomial with roots 2, –3, 4, –5:
POLYCOEF([2,-3,4,-5])
returns[1,2,-25,
-26,120] , representing x
4
+2x
3
–25x
2
–26x+120.