Re: Simplification question

*To*: mathgroup at smc.vnet.net*Subject*: [mg110383] Re: Simplification question*From*: Adriano Pascoletti <adriano.pascoletti at uniud.it>*Date*: Wed, 16 Jun 2010 05:37:51 -0400 (EDT)

Considering the difference of the two sides the answer is returned instantly In[1]:== FullSimplify[1/2 Log[(Exp[a + b] + Exp[-a - b])/(Exp[-a + b] + Exp[a - b])] - ArcTanh[Tanh[a] Tanh[b]], a =E2=88=88 Reals && b =E2=88=88 Reals] Out[1]== 0 Adriano Pascoletti 2010/6/15 Yaroslav Bulatov <yaroslavvb at gmail.com> > I'd like to verify that the following expression is true for a,b real. > It seems to hold numerically. > > 1/2 Log[(Exp[a + b] + Exp[-a - b])/(Exp[-a + b] + Exp[a - b])] ==== > ArcTanh[Tanh[a] Tanh[b]] > > I tried Reduce and combinations of TrigToExp/Simplify with no luck, > any suggestions? > >