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From: Mapsread on 4 Aug 2010 05:50
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?

From: Peter Pein on 4 Aug 2010 07:40
Am Wed, 4 Aug 2010 09:50:45 +0000 (UTC)
schrieb Mapsread <cw_chw(a)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?
>

a value for z

> TIA
>
> P.S. For some reason, Mathematica changes my "*" symbols to "'"
> symbols. Does ' mean multiply?
>

Look in the documentation for "Precision".

Cheers,
Peter

From: David Park on 4 Aug 2010 07:48
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(a)comcast.net
http://home.comcast.net/~djmpark/



From: Mapsread [mailto:cw_chw(a)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?



From: Bob Hanlon on 4 Aug 2010 07:54

` is a number mark

You have an undefined parameter, z

Table[ParametricPlot3D[
{0.5` (x + y), 0.5` (x - y),
z - 0.5` (x^2 - y^2)},
{x, -10, 10},
{y, -10, 10},
ImageSize -> 300],
{z, -10, 10, 10}]


Bob Hanlon

---- Mapsread <cw_chw(a)yahoo.com> wrote:

=============
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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