       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/

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?

```

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