I want to use a different fill for a plot when the curve goes below the x-axis than when it's above that. I tried:
Plot[Sinc[x], {x, 0, 10}, PlotStyle -> Thick, Filling -> 0,
ColorFunction -> Function[{x, y}, If[y < 0, Red, Blue]]]
but then the whole curve has a blue filling. How should I do this?
I expected that this question has been answered before, but I couldn't find it. If it has, my apologies.