HP 39g+, User Manual

Page: 154 / 294

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
.