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NSpire
08-31-2020, 12:39 AM
Post: #1
NSpire
Does one or both NSpire or NSpire CAS have the gamma function? If so, how do I find it?
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08-31-2020, 08:38 AM
Post: #2
RE: NSpire
(08-31-2020 12:39 AM)lrdheat Wrote:  Does one or both NSpire or NSpire CAS have the gamma function? If so, how do I find it?
I don't see the function in my NSpire's docs. I have the non-CAS version but after some googling I'd say the CAS version doesn't have it either.
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08-31-2020, 03:39 PM
Post: #3
RE: NSpire
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.

Nigel (UK)
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08-31-2020, 03:49 PM (This post was last modified: 08-31-2020 03:50 PM by ijabbott.)
Post: #4
RE: NSpire
(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).

— Ian Abbott
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08-31-2020, 04:06 PM
Post: #5
RE: NSpire
(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!

No, that doesn’t work, that I checked right after I didn’t find the gamma function in the docs. Simple google-fu shows there are multiple ways how to add the function if needed though...
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09-01-2020, 10:23 AM
Post: #6
RE: NSpire
(08-31-2020 04:06 PM)vaklaff Wrote:  
(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!

No, that doesn’t work, that I checked right after I didn’t find the gamma function in the docs. Simple google-fu shows there are multiple ways how to add the function if needed though...

2.7! = 4.1706517838 on my TI 86 ...
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09-01-2020, 07:40 PM
Post: #7
RE: NSpire
(09-01-2020 10:23 AM)Pekis Wrote:  
(08-31-2020 04:06 PM)vaklaff Wrote:  No, that doesn’t work, that I checked right after I didn’t find the gamma function in the docs. Simple google-fu shows there are multiple ways how to add the function if needed though...

2.7! = 4.1706517838 on my TI 86 ...

That doesn’t work on Nspire. Sorry for not being clear...
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