Re: Plotting a parametric equation

*To*: mathgroup at smc.vnet.net*Subject*: [mg111548] Re: Plotting a parametric equation*From*: "David Park" <djmpark at comcast.net>*Date*: Wed, 4 Aug 2010 07:47:52 -0400 (EDT)*References*: <20371928.1280916320247.JavaMail.root@n11>

The following works for me: f[x_, y_] := 1/2 {x + y, x - y, x^2 - y^2} ParametricPlot3D[ f[x, y], {x, -1000000, 1000000}, {y, -1000000, 1000000}, BoxRatios -> {1, 1, 1/4}] But I don't know why your * symbols are being changed and I would certainly regard it as a problem and contact WRI Support. What does the InputForm, or FullForm look like? What does the underlying expression look like? (Use Shift+Ctrl+E, or Menu/Format/Show Expression on the cell.) David Park djmpark at comcast.net http://home.comcast.net/~djmpark/ From: Mapsread [mailto:cw_chw at yahoo.com] Greetings, I would like to see the graph of u=.5(x+y), v=.5(x-y), w= z - .5(x^2 - y^2). I entered this into the command-line of Mathematica: ParametricPlot3D[{0.5` (x + y), 0.5` (x - y), z - 0.5` (x^2 - y^2)}, {x, -1000000, 1000000}, {y, -1000000, 1000000}] All I get is a big empty box spanning from -1 to 1 on all sides. Is there something I need to do to make this work? TIA P.S. For some reason, Mathematica changes my "*" symbols to "'" symbols. Does ' mean multiply?