Virgil
Posts:
8,833
Registered:
1/6/11


Re: Help with identity
Posted:
May 8, 2013 2:45 AM


In article <v4sjo8hvdpgibvjlqa3chup5qo4e1at44b@4ax.com>, AP <marc.pichereau@wanadoo.fr.invalid> wrote:
> >Would greatly appreciate any pointers to proving the following > >identity that I came across in Bateman's book on partial > >differential equations: > > > >sinh(x)/(cosh(x)  cos(y) = 1 + > > > > sum{n, 1, inf} [exp(nx)*cos(ny)]
sinh(x)/(cosh(x)  cos(y) =
should be
sinh(x)/(cosh(x)  cos(y) ) = 

