Re: Simplification question

*To*: mathgroup at smc.vnet.net*Subject*: [mg110381] Re: Simplification question*From*: Daniel Huber <danielphuber at gmail.com>*Date*: Wed, 16 Jun 2010 05:37:29 -0400 (EDT)*References*: <hv76mt$k6e$1@smc.vnet.net>

Hi, sometimes mathematica needds just a little help from a friend... Assuming[Element[{a, b,}, Reals], 1/2 Log[(Exp[a + b] + Exp[-a - b])/(Exp[-a + b] + Exp[a - b])] == ArcTanh[Tanh[a] Tanh[b]] // TrigToExp // Simplify] cheers, Daniel Am 15.06.2010 08:30, schrieb Yaroslav Bulatov: > 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? >