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Re: This should evaluate to zero

• To: mathgroup at smc.vnet.net
• Subject: [mg40018] Re: This should evaluate to zero
• From: atelesforos at hotmail.com (Orestis Vantzos)
• Date: Sun, 16 Mar 2003 02:20:37 -0500 (EST)
• References: <b4mnhk$iig$1@smc.vnet.net> <b4pg2c$c06$1@smc.vnet.net> <b4s8k6$iec$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

In any case,
FullSimplify[(3363+2378*Sqrt[2])^1/10]
does return 1+Sqrt[2]

Orestis


jf.alcover at bdpme.fr (jf alcover) wrote in message news:<b4s8k6$iec$1 at smc.vnet.net>...
> atelesforos at hotmail.com (Orestis Vantzos) wrote in message news:<b4pg2c$c06$1 at smc.vnet.net>...
> > Actually, ArcSinh[1] is equal to Log[1+Sqrt[2]]
> 
> Orestis,
> 
> You're right, and Mathematica 'knows' that but it seems not to know
> that it's also equal to Log[3363+2378*Sqrt[2]]/10
> 
> The most straightforward solution to this trouble seems to be the one provided
> by Vladimir Bondarenko <vvb at mail.strace.net> :
> 
> In[1] := expr = ArcSinh[1]-Log[3363+2378*Sqrt[2]]/10;
> 
> In[2] := FullSimplify[expr, ComplexityFunction -> Length]
> 
> Out[2] = 0
> 
> ------
> jfa