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Re: Trouble with an integral

• To: mathgroup at smc.vnet.net
• Subject: [mg57423] Re: Trouble with an integral
• From: "Scout" <user at domain.com>
• Date: Fri, 27 May 2005 04:57:22 -0400 (EDT)
• References: <d741q1$iff$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

"Valeri Astanoff" <astanoff at yahoo.fr> ha scritto nel messaggio 
news:d741q1$iff$1 at smc.vnet.net...
> Bonjour le groupe,
>
> Could someone give me the right answer
> for this integral with parameter 'a' ?
>
> In[1]:=$Version
>
> Out[1]=5.0 for Microsoft Windows (November 18, 2003)
>
> In[2]:=Integrate[Sqrt[1+Sqrt[x]]/(2*Sqrt[2]*E^(a*x)*Sqrt[x]),{x,0,1},
>  Assumptions -> a>0]
>
> Out[2]=(1/3)*(4 - Sqrt[2])
>

                This output is referring to a==0, NOT a>0 .
                The integral is unvaluable in that form.

> In[3]:=%//N
>
> Out[3]=0.861929
>
> In[4]:=NIntegrate[Sqrt[1+Sqrt[x]]/(2*Sqrt[2]*E^(2*x)*Sqrt[x]),{x,0,1}]
>
> Out[4]=0.491465
>

                This is the right answer for a==2.

>
>
> Thanks in advance.
>
> v.a.
>

        ~Scout~