Re: Question about MeshFunctions (Plot function)
- To: mathgroup at smc.vnet.net
- Subject: [mg105084] Re: Question about MeshFunctions (Plot function)
- From: dh <dh at metrohm.com>
- Date: Fri, 20 Nov 2009 06:39:51 -0500 (EST)
- References: <he36de$ec9$1@smc.vnet.net>
Vicent wrote:
> Hello.
>
> Thank you for all your answers to my previous question. They were very useful.
>
> I have a question related to the MeshFunctions option in the Plot function.
>
> I've tried this
>
> Plot[ f[x] , {x , 5 , 10} , Frame -> True , PlotRange -> { 2 ,
> 4 } , AspectRatio -> 1/GoldenRatio , PerformanceGoal -> "Quality"
> ,
> Mesh -> { { 0. } } , MeshFunctions -> { f1[#] & , f2[#] & } ,
> MeshStyle -> { Directive[ PointSize[ Large ] , Red ] , Directive[
> PointSize[ Large ] , Blue ] } ]
>
> and it works OK: it plots the curve for f[x] and marks (in my case)
> two points on it: one red and one blue, at the points where functions
> f1[x] and f2[x] take value 0.
>
> I could do the same with other different functions g[x], g1[x] and g2[x].
>
> But, is it possible to draw both curves in the same frame?? I don't
> know which is the proper syntax --I mean, this:
>
> Plot[ { f[x] , g[x] } , {x , 5 , 10} , Frame -> True ,
> PlotRange -> { 2 , 4 } , AspectRatio -> 1/GoldenRatio ,
> PerformanceGoal -> "Quality" ,
> Mesh -> { { 0. } } , MeshFunctions -> { { f1[#] & , f2[#] & } , {
> g1[#] & , g2[#] & } },
> MeshStyle -> { Directive[ PointSize[ Large ] , Red ] , Directive[
> PointSize[ Large ] , Blue ] } ]
>
> produces an error message. How can I get the kind of graphic I want?
>
> By the way (and this is another question, in fact), as I've just tried
> to explain, I decided to use "MeshFunctions" in order to draw a curve
> with three parts distinguished in it (the boundaries being the red and
> the blue point, I mean). I also was trying to do it with the
> "RegionFunction" option of the "Plot" sentence, but I couldn't get the
> same result (I don't want the curve to be drawn only within a given
> range, but I want the whole curve to be drawn and the different parts
> of the curve to be indicated). The different parts of the curve f[x]
> are bounded by the zeros of the functions f1[x] and f2[x], in my
> example.
>
> Are there any other ways to get what I want??
>
> Please, if I didn't manage to explain my questions clearly enough, let
> me know. I could attach a picture of what I want to draw.
>
> Thank you in advance.
>
Hi, here is an example:
Plot[{3 + Cos[x], 3 + Sin[x]}, {x, 5, 10}, Frame -> True,
PlotRange -> {2, 4}, AspectRatio -> 1/GoldenRatio,
PerformanceGoal -> "Quality", Mesh -> {{0}},
MeshFunctions -> {#1 - 6 &, #1 - 7 &},
MeshStyle -> {Directive[PointSize[Large], Red],
Directive[PointSize[Large], Blue]}]
Daniel