也许这会帮助您开始解决问题。它在表面上绘制了三个随机点。您可以通过设置nPoints来更改点数。我不知道如何沿x轴绘制切线。但是当您弄清楚后,可以使用箭头,正如@Verbeia建议的那样。
nPoints = 3;
Show[ParametricPlot3D[{
{u, v, (Cos[u] + Cos[v])/3},
{u, -1, (Cos[u] + Cos[0])/3}, {5, v, (Cos[4] + Cos[v])/3}},
{u, -4, 4}, {v, 0, 8}, Axes -> False,
Boxed -> False, BoxRatios -> {8, 8, 1.5},
PlotStyle -> Directive[Opacity[0.5]]],
Graphics3D[{Red, PointSize[.025],
Point[Table[{u1 = RandomReal[{-3, 3}], v1 = RandomReal[{1, 7}],
(Cos[u1] + Cos[v1])/3}, {nPoints}]]}]]
![点的分布](https://istack.dev59.com/puazq.webp)
编辑
以下动态变化使用了 @belisarius 的贡献:
Manipulate[
Show[ParametricPlot3D[{{u, v, (Cos[u] + Cos[v])/3} },
{u, -4, 4}, {v, 0, 8}, Axes -> False, Boxed -> False,
BoxRatios -> {8, 8, 1.5},
Mesh -> None,
ImageSize -> {400, 300},
PlotRange -> {{-4, 4}, {0, 8}},
PlotRangePadding -> {{0, 1.4}, {0, 0}},
PlotStyle -> Directive[Opacity[0.5]]],
Graphics3D[({Red, PointSize[.025],
Point@f[pt[[1, 1]], pt[[1, 2]]], Black,
Arrow[{f[pt[[1, 1]], pt[[1, 2]]],
f[pt[[1, 1]], pt[[1, 2]]] + D[f[t, pt[[1, 2]]], t] /.
t -> pt[[1, 1]]}]}]],
Grid[{{
LocatorPane[Dynamic[pt],
Dynamic[Graphics[{},
PlotRange -> {{-4, 4}, {0, 8}},
Frame -> True,
ImageSize -> 160,
FrameTicks -> {Range[-4, 4], Range[0, 8], None, None},
FrameLabel -> {"u", "v"},
GridLines -> {Range[-4, 4], Range[0, 8]},
GridLinesStyle -> Directive[LightGray]]],
{{-4, 0}, {4, 8}}]}}],
{{pt, {{1, 2}}}, ControlType -> None},
Initialization :> {f[u_, v_] := {u, v, (Cos[u] + Cos[v])/3};}]
![Manipulate](https://istack.dev59.com/Li47x.webp)