Just primitive ColorFunction

*To*: mathgroup at smc.vnet.net*Subject*: [mg87348] Just primitive ColorFunction*From*: Šerých Jakub <Serych at panska.cz>*Date*: Tue, 8 Apr 2008 05:37:53 -0400 (EDT)

I think, that it must be something very simple, but I cannot find the solution.... I need to fill the Plot so, that area above the axis will be red and area below the axis will be blue. I tried it in a such way: Plot[Sin[x], {x, 0, 4 Pi} , AxesOrigin -> {0, 0}, Axes -> {True, True}, PlotStyle -> Thick, ColorFunction -> If[Sin[x] >= 0, RGBColor[1, 0, 0], RGBColor[0, 0, 1]], Filling -> Axis, ImageSize -> {380, 280}] But Mathematica says, that If is not a valid Color. If I try it with Function (according to examples in ColorFunction help), ColorFunction -> Function[x, If[Sin[x] >= 0, RGBColor[1, 0, 0], RGBColor[0, 0, 1]]], it is working, but the color of Filling is red allover the range. Thanks for any hint, how to achieve the +Red/-Blue filling. Jakub

**Follow-Ups**:**RE: Just primitive ColorFunction***From:*"Jose Luis Gomez" <jose.luis.gomez@itesm.mx>