Re: Integration question
- To: mathgroup at smc.vnet.net
- Subject: [mg21110] Re: Integration question
- From: Harald Giese <giese at dkrz.de>
- Date: Fri, 17 Dec 1999 01:21:09 -0500 (EST)
- Organization: Institut fuer Meereskunde, Universitaet Hamburg
- References: <831ivc$dgf@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
V Stokes wrote: > > Please try the following simple tests: > > Integrate[Exp[x-a],x] > > then, > > Integrate[Exp[x-a],{x,-Infinity,a}] > > I get the following solution (with Mathematica 3.01) > > If[a<0,1,...] > > Is this the intended solution for this integral? A simple calculation > shows that this integral will evaluate to 1 for any a > 0 ! > Virgil, you don't need Mathematica to do this calculation. Any textbook on analysis should tell you that D[Exp[x-a]] -> Exp[x-a], and, of course, Integrate[Exp[x-a],x] -> Exp[x-a] Integrate[Exp[x-a],{x,-Infinity,a}] -> (Exp[a-a] - Exp[-Infinity-a]) -> (Exp[0] - Exp[-Infinity]) -> (1 - 0) -> 1 Regards, Harald --- This message was entirely written using recycled electrons --- Harald Giese Email: giese at dkrz.de Phone: +49 (0)40 42838 5796; Fax: +49 (0)40 5605724 Institut fuer Meereskunde der Universitaet Hamburg (Institute of Oceanography of the University of Hamburg) Troplowitzstrasse 7, D-22529 Hamburg