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Plot 3D Ln(x^2) Function?

Qian Lu

Posted 8 years ago

I am doing a project for my college calculus class. Revolve the region bonded by the graphs of y=0.5Ln(x^2), y=0, y=-0.6, x=0 about then y-axis When I try to use Mathematica to graph the 3d mode, all I get is just a blank cube. Please help me!!! Thank you!

POSTED BY: Qian Lu

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Mariusz Iwaniuk

Mariusz Iwaniuk, engineer, math hobbyist.

Posted 8 years ago

You made a syntax mistake.Try: RevolutionPlot3D[0.5Log[x^2], {x, 0, 1}, RevolutionAxis -> {0, 0, 1},PlotStyle -> FaceForm[Red, Blue]] Create a thick surface for 3D printing: RevolutionPlot3D[0.5Log[x^2], {x, 0.1, 1}, RevolutionAxis -> {0, 0, 1}, PlotTheme -> "ThickSurface", MaxRecursion -> 4] Regards,MI

You made a syntax mistake.Try:

  RevolutionPlot3D[0.5*Log[x^2], {x, 0, 1}, RevolutionAxis -> {0, 0, 1},PlotStyle -> FaceForm[Red, Blue]]

Create a thick surface for 3D printing:

 RevolutionPlot3D[0.5*Log[x^2], {x, 0.1, 1}, RevolutionAxis -> {0, 0, 1}, PlotTheme -> "ThickSurface", MaxRecursion -> 4]

Regards,MI

POSTED BY: Mariusz Iwaniuk

Qian Lu

Posted 8 years ago

Thank you very much! But I am still confused about 2 questions: (1) We can only use Log function instead of Ln function? (2) How do I set the limit of the height? Because I only want this function's height goes from (y=-0.6 to y=0) I really appreciate your time!

POSTED BY: Qian Lu

Mariusz Iwaniuk

Mariusz Iwaniuk, engineer, math hobbyist.

Posted 8 years ago

Log[x] gives the natural logarithm of x and function is builid-in,but we can defining: Ln[x_] := Log[x]; Limit of the height we can adjust by PlotRange. PlotRange -> {{Range for X}, {Range for Y}, {Range for Z}} Ln[x_] := Log[x]; RevolutionPlot3D[0.5Ln[x^2], {x, 0, 1}, RevolutionAxis -> {0, 0, 1}, PlotStyle -> FaceForm[Red, Blue], PlotRange -> {Automatic, {-0.6, 0}, Automatic}] RevolutionPlot3D[0.5Ln[x^2], {x, 0, 1}, RevolutionAxis -> {0, 0, 1}, PlotStyle -> FaceForm[Red, Blue], PlotRange -> {{-0.6, 0}, {-0.6, 0}, Automatic}]

Log[x] gives the natural logarithm of x and function is builid-in,but we can defining:

Ln[x_] := Log[x];

Limit of the height we can adjust by PlotRange. PlotRange -> {{Range for X}, {Range for Y}, {Range for Z}}

  Ln[x_] := Log[x];
  RevolutionPlot3D[0.5*Ln[x^2], {x, 0, 1}, RevolutionAxis -> {0, 0, 1}, 
  PlotStyle -> FaceForm[Red, Blue], 
  PlotRange -> {Automatic, {-0.6, 0}, Automatic}]

   RevolutionPlot3D[0.5*Ln[x^2], {x, 0, 1}, RevolutionAxis -> {0, 0, 1}, 
   PlotStyle -> FaceForm[Red, Blue], 
   PlotRange -> {{-0.6, 0}, {-0.6, 0}, Automatic}]

POSTED BY: Mariusz Iwaniuk