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Re: This should evaluate to zero

• To: mathgroup at smc.vnet.net
• Subject: [mg40004] Re: This should evaluate to zero
• From: jf.alcover at bdpme.fr (jf alcover)
• Date: Fri, 14 Mar 2003 04:47:30 -0500 (EST)
• References: <b4mnhk$iig$1@smc.vnet.net> <b4pg2c$c06$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

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