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The ! Command

Command Summary Command Syntax Calculator Compatibility Token Size
Calculates the factorial of a number or list. value! TI-83/84/+/SE 1 byte

Press:
1. MATH to access the math menu.
2. LEFT to access the PRB submenu.
3. 4 to select !, or use arrows.

The ! Command

! is the factorial function, where n! = n(n-1)! and 0! = 1, n* an nonnegative integer. The function also works for arguments that are half an odd integer and greater than -1/2: \((-\frac1{2})!\) is defined as \(\sqrt{\pi}\) and the rest are defined recursively. 69 is the largest number for which the calculator can perform the operation. 

3!
     6
(‾.5)!
     1.772453851
Ans²
     3.141592654

The combinatorial interpretation of factorials is the number of ways to arrange n objects in order.

Error Conditions

  • ERR:DOMAIN for any numbers except the ones mentioned above.
Authors: KG