RE: Problems with Plot in Mathematica 4.0, Combining Plots with Different Domains

*To*: mathgroup at smc.vnet.net*Subject*: [mg45846] RE: [mg45806] Problems with Plot in Mathematica 4.0, Combining Plots with Different Domains*From*: "David Park" <djmp at earthlink.net>*Date*: Tue, 27 Jan 2004 04:50:39 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Manfred, There are a number of ways to combine two plots with different domains. Let's define your two functions. f1[x_] := 1/2x^2 - x f2[x_] := -1/2x^2 + x We could combine them into one function using UnitSteps and make a regular Plot. f[x_] := f1[x](UnitStep[x + 3] - UnitStep[x]) + f2[x](UnitStep[x] - UnitStep[x - 3]) Plot[f[x], {x, -4, 4}, Frame -> True, PlotRange -> All]; But if you want to deal with them as separate functions you could combine two plots with the following statement. Block[{$DisplayFunction = Identity}, g1 = Plot[f1[x], {x, -3, 0}]; g2 = Plot[f2[x], {x, 0, 3}]; ] Show[g1, g2, Frame -> True, PlotRange -> {{-4.1, 4.1}, All}]; Here the Block statement gives a local value to $DisplayFunction so as to supress the side plots. Or you could use the DisplayTogether command from Graphics`Graphics`. Needs["Graphics`Graphics`"] DisplayTogether[ Plot[f1[x], {x, -3, 0}], Plot[f2[x], {x, 0, 3}], Frame -> True, PlotRange -> {{-4.1, 4.1}, All}]; The last two methods are sometimes a little tricky because they don't always pick up all Options from the second plot. Another method is to try the DrawGraphics package from my web site below. Needs["DrawGraphics`DrawingMaster`"] Draw2D[ {Draw[f1[x], {x, -3, 0}], Draw[f2[x], {x, 0, 3}]}, Frame -> True, PlotRange -> {{-4.1, 4.1}, All}]; Here the Draw statements are like the Plot statement except they just extract the primitive graphics without making side plots. You could easily add in other plot type graphics and Lines, Points, Text primitives or graphics directives, or you could manipulate the primitive graphics before drawing. David Park djmp at earthlink.net http://home.earthlink.net/~djmp/ From: Manfred Fischer [mailto:manfis at t-online.de] To: mathgroup at smc.vnet.net Hi, I want to plot the two functions in one Plot output +0.5x^2-x (definition-range -3<=x<=0) -0.5x^2+x (definition-range 0<=x<=3) I can't find a mathematica 4.0 solution, please help! -ManFis -