Re: plot bug
- To: mathgroup at smc.vnet.net
- Subject: [mg16734] Re: [mg16656] plot bug
- From: "Wolf, Hartmut" <hwolf at debis.com>
- Date: Wed, 24 Mar 1999 02:23:49 -0500
- Organization: debis Systemhaus
- References: <199903191754.MAA09828@smc.vnet.net.>
- Sender: owner-wri-mathgroup at wolfram.com
Dear Arnold
Arnold Knopfmacher schrieb:
>
> Using Mathematica 3.0 on a Mac and on a PC, the following command
>
> Plot[Cos[Degree Tan[Degree Sin[x]]],{x,0,2 Pi}]
>
> produced a graph whose y axis labels were ALL 1.
> Any explanation?
>
If you just plot that, it comes as a surprise. However, if observe what
you are doing, e.g. with
In[2]:=
showMe[aStart_, aEnd_, n_Integer/;n>1, plotOptions___]:=
Module[{ aStep=(aEnd-aStart)/(n-1), i},
Do[g[i]=With[{a= aStart+aStep(i-1)},
Plot[Cos[a Tan[a Sin[x]]],{x,0,2 Pi},PlotLabel->a,
DisplayFunction->Identity, plotOptions]],{i,n} ];
Show[GraphicsArray[Table[Array[g,3, i],{i,1,n,3}]],
DisplayFunction->$DisplayFunction] ]
then there is now surprise!
Please checkout
In[3]:= showMe[1., 0.5, 24, PlotRange->{{0,2 Pi},{0,1}}]
and then
In[4]:= showMe[1., Degree, 24, AxesOrigin->{0,1}]
you will see something!
There is nothing mysterious with Degree, it only happens to be quite
small!
In[5]:= {Cos[0], Cos[Degree]}//N
Out[5]= {1.,0.999848}
Furthermore you might like to see what happens with:
In[6]:= showMe[1.0, Pi/2, 24, PlotPoints->1000]
Then Tan[Pi/2] becomes quite large, and the Cos of that becomes quite
rapidely oscillating.
I think the question is, what did you _mean_ with a = Degree exactly?
your's Hartmut
- References:
- plot bug
- From: "Arnold Knopfmacher" <arnoldk@gauss.cam.wits.ac.za>
- plot bug