Gamma function differences? « Next Oldest | Next Newest »

 ▼ Nelson M. Sicuro (Brazil) Senior Member Posts: 301 Threads: 28 Joined: Jan 2005 08-30-2003, 11:40 PM Hi to all! I was just playing with my hp-42S and my newly arrived (and fixed!) HP-11C, and I found this difference: In the Gamma function (in HP-11C shared with factorial [n!]) I found these results: HP-11C: n = 68.5, result = 2.056343638e97 HP-42S: n = 68.5, result = 3.0019615151e95 HP-11C: n = 67.5, result = 3.00196151e95 HP-42S: n = 67.5, result = 4.44735039275e93 HP-11C: n = 66.5, result = 4.447350392e93 Commodore SR4190: n = 68.5, result = 3.00196151995e95 Commodore SR4190: n = 67.5, result = 4.44735039501e93 I'm just curious (as I don't have the HP-11C user's manual): the argument for Gamma function in the HP-11C is added by 1 internally? Regards, Nelson ▼ Brandon Del Bel Junior Member Posts: 31 Threads: 3 Joined: Jan 1970 08-31-2003, 01:21 AM Dude, gamma(x)=(x-1)! To calculate gamma(68.5) on your 11c, you need calculate the factiorial of 67.5 to get 3.001961515*10^95 (which is what you got for for your "n=67.5" except for the last decimal; I multiplied the result of 67.5! by 1e-95 to display all the digits.) On a side note, the results of your 42s match my 48gx and 49g. I hope this clarifies the discrepancy. Sincerely, Brandon ▼ Nelson M. Sicuro (Brazil) Senior Member Posts: 301 Threads: 28 Joined: Jan 2005 08-31-2003, 02:08 AM This is because the gamma function in HP-11C is "hidden" in the factorial function? The use of the same key is clever, but as I said I don't have the manual, and I really forgot about the gamma(n) = (n-1)! equivalence... Thanks! Best regards, Nelson ▼ Ellis Easley Posting Freak Posts: 909 Threads: 40 Joined: Jan 1970 08-31-2003, 04:24 AM Viktor Toth has a good discussion of the gamma function at rskey.org:

 Possibly Related Threads... Thread Author Replies Views Last Post HP50g: Writing a function that returns a function Chris de Castro 2 1,272 12-10-2013, 06:49 PM Last Post: Han Trig vs hyperbolic handling differences in Prime CAS Michael de Estrada 3 1,113 11-08-2013, 06:26 PM Last Post: Mark Hardman HP15c continued fraction for Ln(Gamma) Tom Grydeland 0 748 09-30-2013, 05:48 AM Last Post: Tom Grydeland HP Prime emulator: Gamma function Stephan Matthys 28 5,106 08-21-2013, 04:52 PM Last Post: Namir What is the Gamma approximation you use? Namir 21 3,757 08-05-2013, 07:14 AM Last Post: Namir SandMath routine of the week: Inverse Gamma Function Ángel Martin 39 6,490 03-24-2013, 08:19 AM Last Post: peacecalc Article 830 (17bII+ solver differences) Nigel Rowe 2 977 07-28-2012, 11:10 PM Last Post: Nigel Rowe [wp34s] Incomplete Gamma on the wp34s Les Wright 18 3,484 12-06-2011, 11:07 AM Last Post: Namir HP thermal printer differences Alberto Fenini 2 869 08-04-2010, 11:39 AM Last Post: Alberto Fenini Blanknut differences Casey Drew 1 624 06-28-2010, 06:03 PM Last Post: Raymond Del Tondo

Forum Jump: