Re: Why does this happen?
- To: mathgroup at smc.vnet.net
- Subject: [mg78724] Re: Why does this happen?
- From: dh <dh at metrohm.ch>
- Date: Sat, 7 Jul 2007 06:15:12 -0400 (EDT)
- References: <f6ks38$lbm$1@smc.vnet.net>
Hi Budaoy,
look at your integrand. For large x you can neglect 1 and get
Log[Exp[x]/Sqrt[x], but this is Log[Exp[x]]-Log[Sqrt[x]], where the
first part is mach larger than the second. Therefore the integrand is
approx.: x. This means, the integral does not exisit.
hope this helps, Daniel
Budaoy wrote:
> I have a problem in calculating this integral shown below:
>
> Integrate[Log[1+Exp[x]/Sqrt[x]],{x,0,Infinity}]
> Pi^2/6
>
> N[%]
> 1.64493
>
> NIntegrate[Log[1+Exp[x]/Sqrt[x]],{x,0,Infinity}]
> 1.01799
>
> Where does this difference come from and which one is correct?
>
>