Re: fourier transforms
- To: mathgroup at smc.vnet.net
- Subject: [mg17533] Re: fourier transforms
- From: adam.smith at hillsdale.edu
- Date: Fri, 14 May 1999 01:13:07 -0400
- Organization: Deja.com - Share what you know. Learn what you don't.
- References: <7grgk2$e3i@smc.vnet.net> <7h7sdc$kmn@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
I tried it on my machine (Windows NT 4.0) running Mathematica Version 3.0.1 and had the same problems Lucas had with the FourierCosTransform. The FourierSinTransform worked. It could be a system difference or maybe the versions are not identical. I have run into some things that worked under Version 3.0.0 that did not work under 3.0.1 - BesselJZeros in some cases Adam Smith In article <7h7sdc$kmn at smc.vnet.net>, Hendrik van Hees <h.vanhees at gsi.de> wrote: > lucas wrote: > > > > hello, > > > > i am trying to do some fourier transforms with mathematica 3.0. i does > > not behave as i expect, but perhaps i expect too much or do not > > understand enough of mathematica. anyway, check this out. > > > > f[x] = Exp[-m x] > > > > <<Calculus`FourierTransform` > > > > FourierCosTransform[f[x],x,a] > > > > is supposed to return > > > > m/(m^2 + a^2) when m > 0 > > > > but instead it returns the original FourierCosTransform[E^(-m x),x,a], > > which any dummy can figure out. > > > [...] > > My session of Mathematica 3.0 for your problem gives > =============================================================== > In[1]:= <<Calculus`FourierTransform` > > In[2]:= In[2]:= > In[2]:= f[x_]=Exp[-m*x] > > -(m x) > Out[2]= E > > In[4]:= FourierCosTransform[f[x],x,a] > > m > Out[4]= ------- > 2 2 > a + m > > =============================================================== > > My system (although Mathematica is claimed to be independent of the > system) is an intel Celeron 233 running Linux 2.2.5 and Mathematica 3.0 > for students. > > It might be the problem that you have forgotten the underscore in the > definition of the orginal function f! > > -- > Hendrik van Hees Phone: ++49 06159 71-2755 > c/o GSI-Darmstadt SB 3.162 Fax: ++49 06159 71-2990 > Planckstr. 1 mailto:h.vanhees at gsi.de > D-64291 Darmstadt http://theory.gsi.de/~vanhees/vanhees.html > > --== Sent via Deja.com http://www.deja.com/ ==-- ---Share what you know. Learn what you don't.---