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 Searching for an asymptotic to exp[0.5] jaydfox Long Time Fellow Posts: 440 Threads: 31 Joined: Aug 2007 09/13/2014, 11:49 PM (09/13/2014, 07:15 PM)sheldonison Wrote: $\exp(x)\sqrt{x} \approx \sum_{n=0}^{\infty} \frac{x^n}{\Gamma(n+0.5)}\;\;$ Have you seen this excellent asymptotic entire series? I can't explain it, other than it matches the "fakefunc" integral Hey, this reminds me of the generalization I made for the (unscaled) asymptotic binary partition function: (09/09/2014, 07:43 PM)jaydfox Wrote: $ f(x) = \sum_{k=0}^{\infty}\frac{1}{2^{k(k-1)/2} k!} x^k \\ \Rightarrow f(x) = \sum_{k=0}^{\infty}\frac{1}{2^{k(k-1)/2} \Gamma(k+1)} x^k$ Treating Gamma(k) at negative non-positive integers as infinity, and the reciprocal of such as zero, we can take the limit from negative to positive infinity. And we can replace k with (k+b), where b is zero in the original solution, but can now be treated as any real (well, any complex number, but the complex versions are less interesting). $ f_{\beta}(x) = \sum_{k=-\infty}^{\infty}\frac{2^{-(k+\beta)(k+\beta-1)/2}}{\Gamma(k+\beta+1)} x^{k+\beta}$ We can apply the same generalization to exp(x): $ \exp(x) \approx \sum_{k=-\infty}^{\infty}\frac{x^{k+\beta}}{\Gamma(k+\beta+1)}$ Notice that I put "approximately equal". I haven't checked, but I assume it's exactly equal, but only in the sense that it should satisfy the functional equation exp'(x) = exp(x). Now, set beta = 1/2 and truncate the negative powers of x: $ \exp(x) \approx \sum_{k=0}^{\infty}\frac{x^{k+1/2}}{\Gamma(k+3/2)}$ ...and comparing your power series, it easily follows that your power series is asymptotic to exp(x) x^(1/2). Hmm, oh dear, I think you missed a +1 in the Gamma function in your series? (LOL, it's okay, I usually forget the +1 as well.) If you set beta=-1/2, then all is well! $ \frac{\exp(x)}{\sqrt{x}} \approx \sum_{k=0}^{\infty}\frac{x^{k}}{\Gamma(k+1/2)}$ $ \exp(x)\sqrt{x} \approx \sum_{k=0}^{\infty}\frac{x^{k}}{\Gamma(k+3/2)}$ ~ Jay Daniel Fox « Next Oldest | Next Newest »

 Messages In This Thread Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/07/2014, 12:22 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 05/08/2014, 04:25 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 05/10/2014, 12:14 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/10/2014, 11:31 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 05/10/2014, 11:48 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/10/2014, 11:58 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/09/2014, 11:19 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/10/2014, 11:56 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 05/13/2014, 04:23 AM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 05/14/2014, 05:54 AM RE: Searching for an asymptotic to exp[0.5] - by JmsNxn - 05/12/2014, 03:48 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 05/12/2014, 03:56 PM RE: Searching for an asymptotic to exp[0.5] - by JmsNxn - 05/12/2014, 05:06 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/12/2014, 11:35 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/13/2014, 11:44 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/14/2014, 11:42 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 05/15/2014, 06:15 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/15/2014, 09:49 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 05/16/2014, 07:27 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/14/2014, 12:20 AM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 07/17/2014, 05:46 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/15/2014, 08:53 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/16/2014, 09:36 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/16/2014, 10:16 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 05/18/2014, 06:14 PM RE: Searching for an asymptotic to exp[0.5] - by JmsNxn - 05/22/2014, 12:16 AM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 05/22/2014, 07:08 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/22/2014, 08:31 AM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 05/22/2014, 10:16 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/23/2014, 10:53 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 05/25/2014, 03:00 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 05/29/2014, 11:09 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 07/12/2014, 07:46 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/29/2014, 11:32 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 05/29/2014, 11:54 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/30/2014, 09:41 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 06/28/2014, 11:16 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/28/2014, 09:52 PM RE: Searching for an asymptotic to exp[0.5] - by JmsNxn - 06/29/2014, 01:40 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 06/30/2014, 12:56 AM RE: Searching for an asymptotic to exp[0.5] - by JmsNxn - 06/30/2014, 03:21 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 06/30/2014, 11:56 PM RE: Searching for an asymptotic to exp[0.5] - by JmsNxn - 07/01/2014, 12:35 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 06/30/2014, 01:27 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/01/2014, 10:10 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 07/01/2014, 11:41 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/02/2014, 09:53 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/10/2014, 11:48 PM RE: Searching for an asymptotic to exp[0.5] - by MorgothV8 - 07/13/2014, 06:48 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/14/2014, 12:27 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/14/2014, 11:16 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/15/2014, 08:22 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/15/2014, 09:43 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/15/2014, 09:48 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/24/2014, 12:10 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/24/2014, 10:47 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 07/25/2014, 02:46 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/24/2014, 10:54 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/26/2014, 12:21 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/27/2014, 08:37 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/27/2014, 05:01 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/28/2014, 12:17 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/28/2014, 10:30 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 07/30/2014, 04:07 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 08/01/2014, 11:20 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 08/01/2014, 11:36 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 08/02/2014, 12:26 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 08/02/2014, 03:44 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 08/02/2014, 11:02 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 08/02/2014, 11:48 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 08/03/2014, 04:54 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 08/03/2014, 08:46 AM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 08/03/2014, 12:06 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 08/03/2014, 12:10 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 08/05/2014, 11:31 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 08/08/2014, 10:28 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 08/09/2014, 12:24 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 08/10/2014, 06:08 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/01/2014, 10:24 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 09/03/2014, 01:04 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/02/2014, 07:46 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/02/2014, 07:53 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/08/2014, 12:56 AM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 09/08/2014, 04:15 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/08/2014, 11:03 AM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 09/09/2014, 04:33 AM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 09/09/2014, 06:26 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/10/2014, 11:02 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/11/2014, 08:02 AM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 09/11/2014, 02:13 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/12/2014, 07:49 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/12/2014, 06:35 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 09/13/2014, 07:15 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/13/2014, 11:25 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 09/13/2014, 11:45 PM RE: Searching for an asymptotic to exp[0.5] - by jaydfox - 09/13/2014, 11:49 PM RE: Searching for an asymptotic to exp[0.5] - by jaydfox - 09/14/2014, 12:00 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/14/2014, 05:07 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 09/15/2014, 03:53 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/14/2014, 09:34 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/16/2014, 12:14 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/16/2014, 12:27 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/18/2014, 10:20 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/18/2014, 11:07 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/19/2014, 12:23 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/29/2014, 11:40 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/19/2014, 04:02 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 11/03/2014, 01:26 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 11/03/2014, 10:49 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 11/03/2014, 11:34 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 11/03/2014, 11:39 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 11/04/2014, 09:41 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 11/04/2014, 10:38 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 11/05/2014, 11:58 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 11/07/2014, 12:27 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 03/28/2015, 11:11 PM RE: Searching for an asymptotic to exp[0.5] - by marraco - 03/29/2015, 12:59 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/25/2015, 10:24 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 05/25/2015, 10:52 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/15/2015, 06:45 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/15/2015, 06:55 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/17/2015, 01:45 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/18/2015, 09:34 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/18/2015, 09:56 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/18/2015, 10:09 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/31/2015, 04:57 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 07/31/2015, 05:12 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 08/15/2015, 10:22 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 08/16/2015, 02:49 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 08/16/2015, 03:23 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 08/26/2015, 07:36 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/03/2015, 10:31 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/05/2015, 08:16 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/09/2015, 12:17 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/12/2015, 01:14 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/14/2015, 01:30 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/18/2015, 11:31 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/21/2015, 10:53 AM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 09/21/2015, 05:58 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/24/2015, 08:10 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/25/2015, 12:59 AM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 09/25/2015, 08:26 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/26/2015, 12:24 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/29/2015, 12:28 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 10/01/2015, 07:56 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/30/2015, 12:25 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/30/2015, 09:27 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/01/2015, 11:25 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/02/2015, 02:56 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/03/2015, 10:42 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/06/2015, 12:11 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/06/2015, 12:26 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/08/2015, 07:52 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/08/2015, 12:26 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/08/2015, 10:43 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/08/2015, 11:08 PM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 10/09/2015, 08:15 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/09/2015, 11:56 AM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 10/10/2015, 03:08 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/10/2015, 07:40 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/08/2015, 11:12 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/09/2015, 07:18 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/10/2015, 08:15 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/10/2015, 08:26 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/11/2015, 07:17 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/17/2015, 11:59 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/18/2015, 11:07 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/18/2015, 11:22 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/19/2015, 12:20 AM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 10/27/2015, 01:27 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 02/16/2016, 03:17 AM RE: Searching for an asymptotic to exp[0.5] - by sheldonison - 02/18/2016, 06:51 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 02/17/2016, 01:25 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 02/18/2016, 12:53 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 02/18/2016, 01:11 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 02/23/2016, 01:01 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 02/23/2016, 01:23 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 03/21/2016, 01:26 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 04/05/2016, 01:29 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/04/2016, 07:21 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/04/2016, 08:16 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/04/2016, 08:29 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/06/2016, 03:12 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 09/06/2016, 03:47 PM RE: Searching for an asymptotic to exp[0.5] - by tommy1729 - 03/15/2018, 01:23 PM

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