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Re: Plotting a table of piecewise functions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg105416] Re: Plotting a table of piecewise functions
  • From: dh <dh at metrohm.com>
  • Date: Tue, 1 Dec 2009 06:28:10 -0500 (EST)
  • References: <hf2mm2$i8o$1@smc.vnet.net>


michael partensky wrote:

> Hi!

> I have a table of three piecewise functions:

> 

> pdf[x]= {\[Piecewise] {

>    {(x^2/9), 0 <= x <= 3},

>    {0, \!\(\*

>       TagBox["True",

>        "PiecewiseDefault",

>        AutoDelete->False,

>        DeletionWarning->True]\)}

>   }, \[Piecewise] {

>    {0.25 x, 0 < x < 2},

>    {0.5, 2 <= x < 3},

>    {0, \!\(\*

>       TagBox["True",

>        "PiecewiseDefault",

>        AutoDelete->False,

>        DeletionWarning->True]\)}

>   }, \[Piecewise] {

>    {((4 x Cos[x]^2)/\[Pi]^2), 0 < x < \[Pi]},

>    {0, \!\(\*

>       TagBox["True",

>        "PiecewiseDefault",

>        AutoDelete->False,

>        DeletionWarning->True]\)}

>   }}

> 

> I would like to make a plot of it.

> 

> Plot[pdf[x],{x,-1,4},PlotStyle->{Red,Green,Blue}] ignores the colors and

> interrupts some of the curves .

> 

> 

> Plot[{pdf[x][[1]],pdf[x][[2]],pdf[x][[3]]},{x,-1,4},PlotStyle->{Red,Green,Blue}]

> does the job as expected.

> 

> Why are the results different? What is wrong with the first approach?

> 

> Thanks.

> Michael.

> 

> 

Hi Michale,

if you simply say:

Plot[pdf[x],{x,0,4}]

Plot thinks, because Plot has the attribute holdAll, that you are 

plotting one single function. Therefore to expand pdf[x], say e.g.:

Plot[Evaluate@ pdf[x], {x, 0, 10}, PlotRange -> All]



Daniel




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