Re: Integration bug
- To: mathgroup at smc.vnet.net
- Subject: [mg38497] Re: Integration bug
- From: carlos at colorado.edu (Carlos Felippa)
- Date: Fri, 20 Dec 2002 04:25:31 -0500 (EST)
- References: <atp6v0$909$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
"Dana DeLouis" <delouis at bellsouth.net> wrote in message news:<atp6v0$909$1 at smc.vnet.net>...
> I am new to Mathematica also, but I seem to recall a bug in the use of
> the variable "d" before also. This was the first thing I thought of.
> Changing "d" to something like "z" gives the answer of Pi.
The Integrate behavior seems to be connected to lexicographic
ordering of the variables. For example (from 4.2):
ClearAll[x,z,a,b];
Print[Integrate[Cos[x+z]/(x+z)^2,{x,-Infinity,Infinity}] //InputForm];
Print[Integrate[Cos[x+z]/(x+z)^2,{z,-Infinity,Infinity}] //InputForm];
Print[Integrate[Cos[x+z]/(x+z)^3,{x,-Infinity,Infinity}] //InputForm];
Print[Integrate[Cos[x+z]/(x+z)^3,{z,-Infinity,Infinity}] //InputForm];
Print[Integrate[Sin[x+a+b]/(x+a+b),{x,-Infinity,Infinity}] //InputForm];
Print[Integrate[Sin[x+a+b]/(x+a+b),{a,-Infinity,Infinity}] //InputForm];
Print[Integrate[Sin[x+a+b]/(x+a+b),{b,-Infinity,Infinity}] //InputForm];
-Pi
0
-CosIntegral[-z]/2 + CosIntegral[z]/2
0
0
Pi - SinIntegral[-b - x] - SinIntegral[b + x]
0