I have a (continuous) function on the real plane (e. g.
f(x,y)=x^2-x*y) and want to draw contour lines (e. g.
f(x,y)=1 etc.). Furthermore, I want to adjust the region where to do this (e. g. on the square [-3,3]²). The resulting picture should look like this:
I know how to do this in MATLAB (using
contour), but is there any possbility to do this in TikZ? A minimal example doing exactly this would be great!
(A further question: My actual function is the real part of a complex polynomial (e. g.
f(z)=Re(z^2-1)). Of course, I can manually calculate it using
z=x+iy, but is there an elegant way to use this complex term directly in TikZ?)