S4.nb

$x[t_] := t ; y[t_] := Sin[t] a := 0 ; b := 2 Pi ; c := 0 ; d := Pi ; r := 0.5 ParametricPlot3D ... u] Cos[v]/Sqrt[x '[u]^2 + y '[u]^2], r Sin[v]}, {u, a, b}, {v, c, d}, ViewPoint -> {10, 3, 5}]$

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$x[t_] := t ; y[t_] := Sin[t] R[t_] := 0.07 t a := 0 ; b := 2 Pi ; c := 0 ; d := 2 Pi Parametri ... '[u]^2], y[u] + R[u] x '[u] Cos[v]/Sqrt[x '[u]^2 + y '[u]^2], R[u] Sin[v]}, {u, a, b}, {v, c, d}]$

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$p := 5 Plot3D[-Exp[-(x - Sin[y])^4], {x, -p, p}, {y, -p, p}, PlotPoints -> 60]$

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$p := 5 Plot3D[-Exp[-(x - 0.2 Cos[y])^6 - y], {x, -p, p}, {y, -p, p}, PlotPoints -> 60, ViewPoint -> {1, -4, 2}]$

[Graphics:HTMLFiles/index_15.gif]

$p := 3 Plot3D[0.4 Exp[-(x + 0.5)^2 - (y - 1)^2] + 0.5 Exp[-(x - 1)^2 - y^2] + 0.3 Exp[-(x - 1) ... (x + 1)^2 - (y + 2)^2], {x, -p, p}, {y, -p, p}, PlotPoints -> 60, BoxRatios -> {1, 1, 0.3}]$

[Graphics:HTMLFiles/index_19.gif]

Converted by Mathematica (May 15, 2004)