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Re: Bug in Plot3D?

• To: mathgroup at smc.vnet.net
• Subject: [mg105236] Re: Bug in Plot3D?
• From: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>
• Date: Wed, 25 Nov 2009 02:32:45 -0500 (EST)
• References: <hegdsg$t8$1@smc.vnet.net>

As defined here, the functions f and g are a list. You should use the
first part of it instead.

Cheers -- Sjoerd

On Nov 24, 12:52 pm, SixWingedSeraph <wellsober... at gmail.com> wrote:
> The two plot commands in the notebook below should give identical
> outputs, but they don't.  The notebook is posted athttp://abstractmath.org/MM/MmaBugQ.nb
>
> a := 9; b := 18;
>
> ff[x_, y_, z_] := x + y + z
>
> gg[x_, y_, z_] := 2*x - 2*y - z
>
> f[x_, y_] := z /. Solve[ff[x, y, z] == a, z]
>
> f[x, y]
>
> g[x_, y_] := z /. Solve[gg[x, y, z] == b, z]
>
> g[x, y]
>
> Plot3D[{-x - y + 9, 2*(x - y - 9)}, {x, 6, 10}, {y, -5, 1},
>    BoxRatios -> {4, 6, 24}, ViewPoint -> {4.5, 3, 20},
>  MeshStyle -> Gray,
>    AxesLabel -> {x, y, z}, PlotStyle -> {{Red, Opacity[0.7]},
>        {Green, Opacity[0.7]}}, ColorFunction -> White]
>
> Plot3D[{f[x, y], g[x, y]}, {x, 6, 10}, {y, -5, 1},
>    BoxRatios -> {4, 6, 24}, ViewPoint -> {4.5, 3, 20},
>  MeshStyle -> Gray,
>    AxesLabel -> {x, y, z}, PlotStyle -> {{Red, Opacity[0.7]},
>        {Green, Opacity[0.7]}}, ColorFunction -> White]