RE: Strange results from Integrate
- To: mathgroup at smc.vnet.net
- Subject: [mg16065] RE: [mg16022] Strange results from Integrate
- From: "Ersek, Ted R" <ErsekTR at navair.navy.mil>
- Date: Tue, 23 Feb 1999 03:45:20 -0500
- Sender: owner-wri-mathgroup at wolfram.com
Sergio Terrazas:
Reported a problem with Integrate.
______________________
I think he found a problem, but don't agree with some of the results he
posted. I am using Version 3.0.1 with a Windows 95. I get the results
below.
Out[1], Out[2], Out[3], Out[4], and Out[5] below show the right answers.
______________________
In[1]:=
F[x_]=Integrate[Exp[-20(x-125/10)],x]
Out[1]=
-E^(250 - 20*x)/20
In[2]:=
F[Infinity]-F[126/10]
Out[2]=
1/(20*E^2)
In[3]:=
Integrate[Exp[-20(x-125/10)],{x,126/10,Infinity}]
Out[3]=
1/(20*E^2)
In[4]:=
N[%]
Out[4]=
0.006766764161830635
In[5]:=
NIntegrate[Exp[-20(x-12.5)],{x,12.6,Infinity}]
Out[5]=
0.006766764161830801
__________________
Out[6], Out[7], and Out[8] below show wrong answers. I can't explain how it
comes up with these answers.
In[6]:=
Integrate[Exp[-20(x-12.5)],{x,126/10,Infinity}]
Out[6]=
0.
In[7]:=
Integrate[Exp[-20(x-125/10)],{x,12.6,Infinity}]
Out[7]=
3.259257562135177*^91
In[8]:=
Integrate[Exp[-20(x-12.5)],{x,12.6,Infinity}]
Out[8]=
3.259257562135177*^91
___________________
Regards,
Ted Ersek