Gamma function - Printable Version +- HP Forums ( https://www.hpmuseum.org/forum)+-- Forum: HP Calculators (and very old HP Computers) ( /forum-3.html)+--- Forum: HP Prime ( /forum-5.html)+--- Thread: Gamma function ( /thread-15436.html) |

Gamma function - robmio - 08-06-2020 01:56 PM
Hello everyone, I would like to know how to replace "Gamma(a,0)" and "Gamma(a,infinity)" ("a" equal, for example, to 2, or to 1/5, etc.) with "gamma(a)" and with "0" , respectively. For example the following approach does not work: "subst(Gamma (2/3,0), Gamma (a,0), Gamma(a))". How can I do? Sincerely, robmio RE: Gamma function - robmio - 08-06-2020 03:49 PM
For example: laplace(t^(-1/3),t,s) --> (-s*Gamma(2/3,infinity)+s*Gamma(2/3,0))/(s*(s^(2/3))). RE: Gamma function - Major - 08-06-2020 05:17 PM
From what I see the Gamma function only takes one argument unless I am missing something. EDIT: Oh I see it outputs that as an answer I know you can change the expression to a string (STRING) and use the replace (REPLACE) command, but afterwards I am unsure because I do not know how to convert the string back to an expression. There may or may not be a function to change a string into an unsolved expression, but I can't find it. Hopefully someone can help you. But if you want to solve it you can use EXPR. RE: Gamma function - robmio - 08-06-2020 06:14 PM
In HP PRIME, Gamma function can take one argument as "complete" gamma function, or 2 arguments as incomplete gamma function: Gamma(a) = Gamma(a,0) = int(t^(a-1)*exp(-t),t,0,infinity) Gamma(a,x) = int(t^(a-1)*exp(-t),t,x,infinity). In HP PRIME, for example, Gamma(0.5,0) = 1.7724 Gamma(0.5,2) = 0.080647. |