Math, Angle, and Test Operations 2.21
82STAT~4.DOC TI-83 international English Bob Fedorisko Revised: 10/28/05 12:19 PM Printed: 10/28/05 12:20
PM Page 21 of 26
nPr (number of permutations) returns the number of
permutations of items taken number at a time. items and number
must be nonnegative integers. Both items and number can be
lists.
items
nPr number
nCr (number of combinations) returns the number of
combinations of items taken number at a time. items and number
must be nonnegative integers. Both items and number can be
lists.
items
nCr number
! (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)! = nän!, until n is reduced to either 0 or L1/2. At that point, the
definition 0!=1 or the definition (L1à2)!=‡p is used to complete the
calculation. Hence:
n!=nä(nN1)ä(nN2)ä ... ä2ä1, if n is an integer ‚0
n!= nä(nN1)ä(nN2)ä ... ä1à2ä‡p, if n+1à2 is an integer ‚0
n! is an error, if neither n nor n+1à2 is an integer ‚0.
(The variable n equals value in the syntax description above.)
nPr,
nCr
! (Factorial)