Re: Q: ArcTan[ Tan[ x ] ] = x

*To*: mathgroup at christensen.cybernetics.net*Subject*: [mg1963] Re: Q: ArcTan[ Tan[ x ] ] = x*From*: Scott.A.Hill at williams.edu (Lancelot)*Date*: Sun, 27 Aug 1995 23:24:10 -0400*Organization*: Williams College, Williamstown MA

In article <DDuMDu.Joy at wri.com>, Ron Elsner <elsner at avalon.msfc.nasa.gov> wrote: >Suppose I really want Mma to set ArcTan[ Tan[ x ] ] = x, or >ArcSin[ Sin[ x ] ] = x. How do I do this? Unprotect[Tan,ArcTan]; ArcTan[Tan[x_]]:=x; Protect[Tan,ArcTan]; will do it for the first example. Beware however, as changing predefined definitions like that can sometimes unpredictable consequences.... / :@-) Scott \