Plot3D[x^3 - x^2*y, {x, -1, 1}, {y, -1, 1}, 
      PlotRange -> {-2, 2}, Ticks -> None, 
      DisplayFunction -> Identity]

Plot3D[
      1000000000000000000000000000 (y - 1/2), {x, -1, 1}, {y, -1, 
        1}, PlotRange -> {-2, 2}, 
      DisplayFunction -> Identity]

Show[
      Graphics3D[{Hue[0.02], Thickness[0.003], 
          Line[{{-1, 1/2, -7/8}, {1, 1/2, 13/8}}]}], 
      DisplayFunction -> Identity]

Show[%1, %2, %3, ImageSize -> 700, 
        DisplayFunction -> Identity]

Plot[{x^3 - x^2/2, 5/4  x + 3/8}, {x, -1, 1}, Ticks -> None, 
      PlotRange -> {-3/2, 3/2}, ImageSize -> 700, 
      PlotStyle -> {{Thickness[0.003]}, {Hue[0.02], Thickness[0.003]}}, 
      DisplayFunction -> Identity]

Partielle Ableitungen

Die partielle Ableitung gibt die Änderung in Richtung einer Koordinatenachse an.

Show[GraphicsArray[{%4, %5}], ImageSize -> 1250, 
      DisplayFunction -> $DisplayFunction]