line color in figure

I'd like to change the color of the diagonal axis. Please look at the picture below.

[Jan]

Which line is "the diagonal axis"? Please post your code and explain, what you have tried so far. Thanks.

Answer 1

[Stephen23]

If you plot all of the lines at once then they will automatically be colored using the axes ColorOrder:

N = 16;
A = linspace(0,pi,N);
X = cos(A);
Y = sin(A);
X(2,:) = 0;
Y(2,:) = 0;
plot(X,Y)
axis equal

The documentation explains how the ColorOrder can be changed:

https://www.mathworks.com/help/matlab/creating_plots/defining-the-color-of-lines-for-plotting.html

http://www.mathworks.com/matlabcentral/answers/98675-how-can-i-cycle-through-the-colororder-for-my-matlab-figure-when-making-multiple-calls-to-my-plot