Problem to Plot 3d (solved with ContourPlot)

Questions
1

Hello everyone, I would like to plot the equations of two variables written below where
a = const, p = const while the independent variables are r e theta.
I would like to plot such sigmar = constant to vary from r e theta in a fixed interval .Thanks for any responses.

\[Sigma]r[r, \[Theta]] = 
 p/2 (1 - a^2/r^2) + p/2 (1 - (2 a/r)^2 + 3 (a/r)^4) Cos[2 \[Theta]]
\[Sigma]\[Theta][r, \[Theta]] = 
 p/2 (1 + a^2/r^2) - p/2 (1 + 3 (a/r)^4 ) Cos[2 \[Theta]]
\[Tau]r\[Theta][
  r, \[Theta]] = -p/2 (1 + (2 a/r)^2 - 3 (a/r)^4) Sin[2 \[Theta]]

Exemple: I want Sigma r = cost to vary from r and theta.

I’m going to draw the contour lines in the polar reference isotensional!!!

2

Are you using Mathematica to plot it or Wolfram|Alpha?

Square brackets are used for function application in Mathematica. The first step is to get your example into valid code. I’m not sure how to read the notation above. Maybe if you don’t know the proper Wolfram Language syntax, you can provide the syntax in TeX?

Try typing out the functions with basic, unformatted code. Try to not use subscripts. Just use latin characters.

3

Hi Sean ,
I use Mathematica 10 and I would like to draw the level curves . How you doing? I attach the file in LaTex

4

I’ve resolved with the command ContourPlot[ ].