Re: Please explain this weird Integrate result

• To: mathgroup at smc.vnet.net
• Subject: [mg60142] Re: Please explain this weird Integrate result
• From: "Scout" <not at nothing.net>
• Date: Sun, 4 Sep 2005 03:02:05 -0400 (EDT)
• References: <dfbevv\$inu\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```"Jose Reckoner" <reckoner at gmail.com>
>
> Expand[Integrate[(2*x)/(2*x - 1), x]]
>
> gives
>
> -1/2 + x + Log[-1 + 2*x]/2
>
> But,
>
> Expand[Integrate[1 + 1/(-1 + 2*x), x]]
>
> gives
>
> x + Log[-1 + 2*x]/2
>
> even though
>
> (2*x)/(2*x - 1) == 1 + 1/(-1 + 2*x)
>
> Where did the extra -1/2 in the first result come from?
>
Hi Jose,
I don't know why you've obtained these different (and incorrect) results on
the same integral!
On my system (Math.4) it gives:

In[1]:= a=Expand[Integrate[(2*x)/(2*x - 1), x]];
In[2]:= b=Expand[Integrate[1 + 1/(-1 + 2*x), x]];
In[3]:= a==b
Out[3]= True
In[4]:= a
Out[4]= x + Log[-1+2 x] / 2

~Scout~

```

• Prev by Date: Re: Please explain this weird Integrate result
• Next by Date: Re: Please explain this weird Integrate result