Use of Miscellaneous`RealOnly` Package

*To*: mathgroup at smc.vnet.net*Subject*: [mg25253] Use of Miscellaneous`RealOnly` Package*From*: "David Park" <djmp at earthlink.net>*Date*: Sun, 17 Sep 2000 04:47:32 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Dear MathGroup, Is it possible to turn the Miscellaneous`RealOnly` package on and off? Consider the following problem. I want to find the inverse of the following function: F[u_, v_] := {u^3, v - u} eqns = Thread[F[u, v] == {x, y}] {u^3 == x, -u + v == y} sols = Solve[eqns, {u, v}][[1]] {v -> x^(1/3) + y, u -> x^(1/3)} If the above Solve is done with the RealOnly package active, it fails and gives Nonreal for the answers. So I definitely don't want it active at this point. Now I define the inverse: FI[x_, y_] = ({u, v} /. sols) {x^(1/3), x^(1/3) + y} Now when I evaluate FI[-10, -10] // N {1.077217345015942 + 1.865795172362064*I, -8.922782654984058 + 1.865795172362064*I} I obtain the complex root, so I need to load RealOnly package. << Miscellaneous`RealOnly` FI[-10, -10] // N {-2.15443, -12.1544} So sometimes I want it, and sometimes I don't want it. But there seems no way to get rid of it other than quitting the kernel. Does anyone have any suggestions, or a smoother way to do this problem? David Park djmp at earthlink.net http://home.earthlink.net/~djmp/