Operation Manual

TI-83 Plus Math, Angle, and Test Operations 94
items
nCr
number
! (Factorial)
!
(factorial) returns the factorial of either an integer or a multiple of .5. For
a list, it returns factorials for each integer or multiple of .5.
value
must be
‚L
.5 and

69.
value
!
Note: The factorial is computed recursively using the relationship (n+1)! = n
ä
n!,
until n is reduced to either 0 or
L
1/2. At that point, the definition 0!=1 or the
definition (
L
1
à
2)!=
‡p
is used to complete the calculation. Hence:
n!=n
ä
(n
N
1)
ä
(n
N
2)
ä
...
ä
2
ä
1, if n is an integer
‚
0
n!= n
ä
(n
N
1)
ä
(n
N
2)
ä
...
ä
1
à
2
ä
‡p
, if n+1
à
2 is an integer
‚
0
n! is an error, if neither n nor n+1
à
2 is an integer
‚
0.
(The variable n equals
value
in the syntax description above.)