Re: Integration bug?
- To: mathgroup at yoda.physics.unc.edu
- Subject: Re: Integration bug?
- From: Steven M. Christensen <stevec at yoda.physics.unc.edu>
- Date: Thu, 1 Apr 93 22:38:35 EST
Here is how I would handle the previous Integration:
In[1]:= Log[x]/((x - y)*(x - z))
Log[x]
Out[1]= ---------------
(x - y) (x - z)
In[2]:= Apart[%,x]
Log[x] Log[x]
Out[2]= -(----------------) + ----------------
(-x + y) (y - z) (y - z) (-x + z)
In[3]:= Integrate[%[[1]],{x,0,Infinity}] + Integrate[%[[2]],{x,0,Infinity}]
2 1 2 2 1 2
-2 Pi + 3 Log[-] 2 Pi - 3 Log[-]
y z
Out[3]= ------------------ + -----------------
6 (-y + z) 6 (-y + z)
In[4]:= Expand[%]
1 2 1 2
Log[-] Log[-]
y z
Out[4]= ---------- - ----------
2 (-y + z) 2 (-y + z)
In[5]:= Together[%]
1 2 1 2
-Log[-] + Log[-]
y z
Out[5]= ------------------
2 (y - z)
In[6]:= Quit