Re: Simplifying Jacobian elliptic functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg56325] Re: Simplifying Jacobian elliptic functions*From*: John Billingham <John.Billingham at Nottingham.ac.uk>*Date*: Fri, 22 Apr 2005 06:22:51 -0400 (EDT)*References*: <16439696.1114083913364.JavaMail.jakarta@nitrogen.mathforum.org>*Sender*: owner-wri-mathgroup at wolfram.com

> > Unprotect[Plus] > > JacobiDN[p_, k_]^2 + k_ JacobiSN[p_, k_]^2 := 1 > > Protect[Plus] > > > > Thanks for the tip. Why does your suggestion work, > but > > Unprotect[Minus]; > 1 - JacobiSN[p_, m_]^2 := JacobiCN[p, m]^2; > Protect[Minus]; > > doesn't?? OK. Sorry. Having read some help files, I can see that Unprotect[Plus]; JacobiDN[p_, k_]^2 + k_ JacobiSN[p_, k_]^2 := 1 1 + Minus[ JacobiSN[p_, m_]^2] := JacobiCN[p, m]^2; Protect[Plus]; Does the trick. John