Re: UH oh, integration of rational functions has a bug.
- To: mathgroup at smc.vnet.net
- Subject: [mg41715] Re: UH oh, integration of rational functions has a bug.
- From: "news.sf.sbcglobal.net" <test at test.com>
- Date: Mon, 2 Jun 2003 04:35:22 -0400 (EDT)
- References: <bb4vr4$491$1@smc.vnet.net> <bb73ur$bab$1@smc.vnet.net>
- Reply-to: "news.sf.sbcglobal.net" <test at test.com>
- Sender: owner-wri-mathgroup at wolfram.com
I tried it on ver. 4.2 and same problem exists. Why won't Wolfram Research release a patch to fix these kinds of issues?? Or is there a site that patches issues like this already?? thanks, "Carlos Felippa" <carlos at colorado.edu> wrote in message news:bb73ur$bab$1 at smc.vnet.net... > Richard Fateman <fateman at cs.berkeley.edu> wrote in message news:<bb4vr4$491$1 at smc.vnet.net>... > > Mathematica 4.1 > > > > In[1]:= 1 + 5*x + a*x^2 + 10*x^3 + 5*x^4 + x^5 > > > > > > Integrate[1/%, x] > > > > %1 /. a -> 10 > > > > Integrate[1/%, x] > > > > %1 /. a -> c > > > > Integrate[1/%, x] > > > > InputForm[%] ===> > > > > RootSum[1 + 5*#1 + c*#1^2 + 10*#1^3 + 5*#1^4 + #1^5 & , > > Log[x - #1]/(5 + 30*#1^2 + 20*#1^3 + 5*#1^4 + > > 2*#1*Integrate`V[1][6]) & ] > > > > WHAT is THIS ^^^^^^^^^^^^^^^ ?? and why did it not > > appear in the identical problem where there was an "a" > > instead of a "c" ?? > > > > It is somehow dependent on the sequence of commands. > > This might be related to a problem reported in the thread > "Integration Bug" of Dec 2002. My post in that thread was > > ============================================================= > 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 >