Color Contour Plots for Varying Gamma Values in a Simple Equation

[member 428835]

Hi PF!

I'm wondering if anyone knows how to make each plot for $\gamma$ a different color. What I have so far is

\[Gamma] = {0.01, 0.05, 0.1, 0.5, 1, 2};
ContourPlot[(1 + 2 \[Gamma]) \[Sigma]^2 +
   4 \[Gamma] Cos[k\[CapitalDelta]x] \[Sigma] - (1 - 2 \[Gamma]) ==
  0, {k\[CapitalDelta]x, 0, \[Pi]}, {\[Sigma], -1, 1},
 FrameLabel -> {"k\[CapitalDelta]x", "\[Sigma]"}]

 

[jedishrfu]

Maybe this will help:

http://reference.wolfram.com/language/ref/ColorFunction.html

 

[DrClaude]

I don't know a neat way to condense it, but you can do it "by hand" using

f[\[Gamma]_,
  k\[CapitalDelta]x_, \[Sigma]_] := (1 + 2 \[Gamma]) \[Sigma]^2 +
  4 \[Gamma] Cos[k\[CapitalDelta]x] \[Sigma] - (1 - 2 \[Gamma])

Show[ContourPlot[
  f[0.01, k\[CapitalDelta]x, \[Sigma]] == 0, {k\[CapitalDelta]x,
   0, \[Pi]}, {\[Sigma], -1, 1},
  FrameLabel -> {"k\[CapitalDelta]x", "\[Sigma]"},
  ContourStyle -> Black],
ContourPlot[
  f[0.05, k\[CapitalDelta]x, \[Sigma]] == 0, {k\[CapitalDelta]x,
   0, \[Pi]}, {\[Sigma], -1, 1},
  FrameLabel -> {"k\[CapitalDelta]x", "\[Sigma]"},
  ContourStyle -> Orange],
ContourPlot[
  f[0.1, k\[CapitalDelta]x, \[Sigma]] == 0, {k\[CapitalDelta]x,
   0, \[Pi]}, {\[Sigma], -1, 1},
  FrameLabel -> {"k\[CapitalDelta]x", "\[Sigma]"},
  ContourStyle -> Green],
ContourPlot[
  f[0.5, k\[CapitalDelta]x, \[Sigma]] == 0, {k\[CapitalDelta]x,
   0, \[Pi]}, {\[Sigma], -1, 1},
  FrameLabel -> {"k\[CapitalDelta]x", "\[Sigma]"},
  ContourStyle -> Yellow],
ContourPlot[
  f[1, k\[CapitalDelta]x, \[Sigma]] == 0, {k\[CapitalDelta]x,
   0, \[Pi]}, {\[Sigma], -1, 1},
  FrameLabel -> {"k\[CapitalDelta]x", "\[Sigma]"},
  ContourStyle -> Red],
ContourPlot[
  f[2, k\[CapitalDelta]x, \[Sigma]] == 0, {k\[CapitalDelta]x,
   0, \[Pi]}, {\[Sigma], -1, 1},
  FrameLabel -> {"k\[CapitalDelta]x", "\[Sigma]"},
  ContourStyle -> Blue]]

 

[member 428835]

Thank you both; I'll post if I find a quicker way.