Changing Plot Color in Mathematica

[roam]

I want to generate the following plot in Mathematica in red color:

x[t_] := 31 Cos[t] - 7 Cos[31 t/7];
y[t_] := 31 Sin[t] - 7 Sin[31 t/7];
ParametricPlot[{x[t], y[t]}, {t, 0, 19 \[Pi]}]

The above code creates the plot in default black color. So, I tried using this code to make it red:

x[t_] := 31 Cos[t] - 7 Cos[31 t/7];
y[t_] := 31 Sin[t] - 7 Sin[31 t/7];
ParametricPlot[[{x[t], y[t]}, {t, 0, 19 \[Pi]}],
PlotStyle -> {{RGBColor[1,0,0]}}]

Unfortunently it doesn't work and I get errors. Can anybody help with this?

 

[shoehorn]

You've got too many braces! Here's the working code:

x[t_] := 31 Cos[t] - 7 Cos[31 t/7];
y[t_] := 31 Sin[t] - 7 Sin[31 t/7];
ParametricPlot[{x[t], y[t]}, {t, 0, 19 \[Pi]}, 
 PlotStyle -> {RGBColor[1, 0, 0]}]

Alternatively, you can just pass the name of the color directly to PlotStyle:

x[t_] := 31 Cos[t] - 7 Cos[31 t/7];
y[t_] := 31 Sin[t] - 7 Sin[31 t/7];
ParametricPlot[{x[t], y[t]}, {t, 0, 19 \[Pi]}, 
 PlotStyle -> {Red}]

http://img39.imageshack.us/img39/7893/64328066.jpg

 

[oswaler]

I understand your frustration with trying to change the plot color in Mathematica. It can be a bit tricky, but there are a few different ways to achieve the desired result.

One option is to use the PlotStyle option within the ParametricPlot function. This allows you to specify the color and other styling options for the plot. In your case, you could use the RGBColor function to create a red color and apply it to the plot as follows:

ParametricPlot[{x[t], y[t]}, {t, 0, 19 \[Pi]}, PlotStyle -> RGBColor[1, 0, 0]]

Another option is to use the ColorFunction option within ParametricPlot. This allows you to specify a function that will determine the color of each point in the plot based on its coordinates. For example, you could use the following code to create a plot with a color gradient from red to blue:

ParametricPlot[{x[t], y[t]}, {t, 0, 19 \[Pi]}, ColorFunction -> (Blend[{Red, Blue}, #] &)]

I hope this helps you achieve the desired red plot in Mathematica. If you continue to experience errors, it may be helpful to consult the Mathematica documentation or seek assistance from other Mathematica users online.