HP 40gs, User Manual

Page: 165 / 444

Using mathematical functions 13-11
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 18-10.
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
.
POLYEVAL
Polynomial evaluation. Evaluates a polynomial with the
specified
coefficients for the value of x .
POLYEVAL([ coefficients ] , value )
hp40g+.book Page 11 Friday, December 9, 2005 1:03 AM