Plot[Exp[x], {x, -1, 2}]

Plot[x^2 + 3  x - 5, {x, -2, 2}]

Plot[x^2 + 3  x - 5, {x, -20, 20}]

Plot[Cos[x^2], {x, 0, 10}]

Plot[1/x^2, {x, -2, 2}]

g = Plot[{Sin[x], Cos[x]}, {x, 0, 2  Pi}]

Show[g]

Show[g, Axes -> False]

Show[g, Frame -> True]

Plot[Sin[x], {x, 0, 2  Pi}, PlotPoints -> 5]

Plot[1/x^2, {x, -2, 2}, AspectRatio -> Automatic]

Plot[1/x^2, {x, -2, 2}, PlotRange -> {- .1, 2}]

ParametricPlot[{Cos[x], Sin[x]}, {x, 0, 2  Pi}, 
      AspectRatio -> Automatic]

ParametricPlot[{Cos[3  x], Sin[4  x]}, {x, 0, 2  Pi}, 
      AspectRatio -> Automatic]

ParametricPlot3D[{x, x^2, x^3}, {x, 0, 2}]

ParametricPlot3D[{x, x^2, x^3}, {x, 0, 2}, 
      AspectRatio -> 1]

<< RealTime3D`

ParametricPlot3D[{x, x^2, x^3}, {x, 0, 2}, 
      AspectRatio -> 1]

Plot3D[x^2 + y^2, {x, -1, 1}, {y, -1, 1}, 
      Mesh -> False]

Plot3D[x^2 + y^2, {x, -1, 1}, {y, -1, 1}, Mesh -> False, 
      PlotPoints -> 40]

ContourPlot[x^2 + y^2, {x, -1, 1}, {y, -1, 1}, 
      PlotPoints -> 40]

ContourPlot[x^2 + y^2, {x, -2, 2}, {y, -2, 2}, 
      PlotPoints -> 40, Contours -> {1, 2, 3}]

DensityPlot[x^2 + y^2, {x, -1, 1}, {y, -1, 1}, 
      Mesh -> False, PlotPoints -> 100]

ParametricPlot3D[{x^2 + y, x + y^2, x - y}, {x, -1, 1}, {y, 0, 
        2}]

Plot[Sin[1/x], {x, -1/Pi, 1/Pi}, 
      PlotPoints -> 1000]

Plot[Sin[1/x], {x, -1/Pi/10, 1/Pi/10}, 
      PlotPoints -> 1000]

Plot[Sin[1/x], {x, 1/Pi/30, 1/Pi/10}, 
      PlotPoints -> 1000]

Plot3D[x y/(x^2 + y^2), {x, -1, 1}, {y, -1, 1}, 
      PlotPoints -> 100, Mesh -> False]

DensityPlot[x y/(x^2 + y^2), {x, -1, 1}, {y, -1, 1}, 
      PlotPoints -> 500, Mesh -> False]

ContourPlot[(Sin[x] + x y)/(x^2 + y^2), {x, -1, 
        1}, {y, -1, 1}, PlotPoints -> 100]

ParametricPlot3D[{x Cos[y], x Sin[y], y}, {x, 0, 1}, {y, 0, 2  Pi}, 
      AspectRatio ->  .5]

x = 1;
ParametricPlot3D[{x Cos[y], x Sin[y], y}, {y, 0, 2  Pi}, 
        AspectRatio ->  .5];
Clear[x]

x

ParametricPlot[{ Cos[y],  Sin[y], y}, {y, 
        0, 2  Pi}, AspectRatio ->  .5]

ParametricPlot[{Cos[y], Sin[y], y}, {y, 0, 2  Pi}]

Cos[ .3]