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Re: What is wrong with 2Pi?

• To: mathgroup at smc.vnet.net
• Subject: [mg131165] Re: What is wrong with 2Pi?
• From: Bob Hanlon <hanlonr357 at gmail.com>
• Date: Sat, 15 Jun 2013 04:21:48 -0400 (EDT)
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• References: <20130614085855.6E6BC6A61@smc.vnet.net>

I would guess that the problem is related to Manipulate's attribute HoldAll
and that numeric constants like Pi are symbols; however, N can be used
rather than specifying 6.28


{Attributes[Manipulate], Head[Pi]}


{{HoldAll, Protected, ReadProtected}, Symbol}


Manipulate[
 Plot[Sin[a x], {x, 0, 4 Pi},
  PlotRange -> {-1.05, 1.05},
  AxesLabel -> {Style["x", 16, Italic], None}],
 {{a, 1, Style["a", 16, Italic, FontFamily -> "Times"]},
  0, 2 Pi // N,
  VerticalGauge[##, ImageSize -> 60] &},
 ControlPlacement -> Left,
 FrameLabel ->
  Style["sin(a x)", 18, Italic, FontFamily -> "Times"]]



Bob Hanlon




On Fri, Jun 14, 2013 at 4:58 AM, Alexei Boulbitch
<Alexei.Boulbitch at iee.lu>wrote:

> Dear community,
>
> This works:
>
> Manipulate[
>  Plot[Sin[a x], {x, 0, 4 Pi}], {{a, 1}, 0, 6.28,
>   VerticalGauge[##, ImageSize -> 50] &}, ControlPlacement -> Left]
>
> This
>
> Manipulate[
>  Plot[Sin[a x], {x, 0, 4 Pi}], {{a, 1}, 0, 2 \[Pi],
>   VerticalGauge[##, ImageSize -> 50] &}, ControlPlacement -> Left]
>
> however, does not work. I cannot move the gauge in this latter case, while
> it is easy to move it in the former one.
>
> So, if I am right, is it Pi placed instead of 6.28 that disturbs the
> functioning? Please check it. Looks like a bug.
>
> Alexei
>
>
> Alexei BOULBITCH, Dr., habil.
> IEE S.A.
> ZAE Weiergewan,
> 11, rue Edmond Reuter,
> L-5326 Contern, LUXEMBOURG
>
> Office phone :  +352-2454-2566
> Office fax:       +352-2454-3566
> mobile phone:  +49 151 52 40 66 44
>
> e-mail: alexei.boulbitch at iee.lu
>
>
>
>
>

• References:
  • What is wrong with 2Pi?
    • From: Alexei Boulbitch <Alexei.Boulbitch@iee.lu>