Help reduce this expression (Not Long)

*To*: mathgroup at christensen.cybernetics.net*Subject*: [mg1977] Help reduce this expression (Not Long)*From*: Vlad.Fridkin at manuel.anu.edu.au*Date*: Mon, 4 Sep 1995 22:21:16 -0400*Organization*: Australian National University

Here it is. I didn't want to send the expression in its glory since it is too long. So I send this expression and a few rules to get to the big one: Dn[a_,k_] := Sqrt[1 - k^2 Sn[a,k]^2]; Cn[a_,k_] := Sqrt[1 - Sn[a,k]^2]; ellirule := {Sn[u_+v_,k_] -> (Sn[u,k]Cn[v,k]Dn[v,k] + Cn[u,k]Sn[v,k]Dn[u,k])/ (1-k^2 Sn[u,k]^2 Sn[v,k]^2)} sngone := Sn[x_,k_]-> x; In[1]:= Sn[v, k]*Sn[2*y, k]^2 + Sn[u - v, k]*Sn[2*y, k]*Sn[u + 2*y, k] - Sn[u, k]*Sn[2*y, k]*Sn[u - v + 2*y, k] - k^2*Sn[u, k]*Sn[u - v, k]*Sn[v, k]*Sn[2*y, k]^2*Sn[u + 2*y, k]* Sn[u - v + 2*y, k] In[2]:= % /. ellirule; In[3]:= % /. ellirule; In[4]:= % /. sngone Out[4]= Lots of stuff I cannot simplify to become zero. Has anyone out there got experience working with elliptic functions in an algebraic way? Thanks for any help. Vlad. -- ___________________________ Vlad.Fridkin at anu.edu.au || ||| || ||| || ||| || ||| http://wwwmaths.anu.edu.au/~vxf661/Vlad_Fridkin.html