NSpire

[ijabbott]

(08-31-2020 03:39 PM)Nigel (UK) Wrote:  On my (ancient, compared to the NSpire) TI-86 the factorial function takes fractional arguments - e.g., 2.7! If the NSpire does this you can find the gamma function, because gamma(x) = (x-1)!. I don't know whether the NSpire factorial function works for complex numbers (the TI-86 doesn't), but if you are interested in gamma(x) for real x this may help.

Unfortunately, the factorial operator only works on integers on the TI-NSpire, and it's the same on the TI-89 series.

BTW, the "factorial" function on real or complex domain is a.k.a. the "pi" function, that is: gamma(x) = pi(x-1).