Re: Question about Manipulate

*To*: mathgroup at smc.vnet.net*Subject*: [mg122759] Re: Question about Manipulate*From*: Daniel Lichtblau <danl at wolfram.com>*Date*: Thu, 10 Nov 2011 06:50:01 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <201111091124.GAA11113@smc.vnet.net>

On 11/09/2011 05:24 AM, mailcwc at gmail.com wrote: > I tried the following code in Mathematica 8.0 > > Clear["Global`*"] > f = Sin[a x + b] > Manipulate[Plot[f, {x, 0, 4 \[Pi]}], {a, 0.5, 2}, {b, 0, 2 \[Pi]}] > > The Manipulate block is showed, but the Sin function is not plotted. > > When I replace f in the third line with its definition, > > Clear["Global`*"] > Manipulate[ Plot[Sin[a x + b], {x, 0, 4 \[Pi]}], {a, 0.5, 2}, {b, 0, 2 > \[Pi]}] > > The Sin function is plotted. > > Is this a bug or a limitation in Mathematica? > This does seem to be an FAQ. See Documentation Center > Manipulate > Possible Issues Third item begines: "Manipulate only "notices" explicit visible parameters:" and goes on to show how this should generally be handled (with almost the same example as yours). In this case one would do f[a_, b_] = Sin[a*x + b] Manipulate[ Plot[f[a, b], {x, 0, 4 \[Pi]}], {a, 0.5, 2}, {b, 0, 2 \[Pi]}] Daniel Lichtblau Wolfram Research

**References**:**Question about Manipulate***From:*"mailcwc@gmail.com" <mailcwc@gmail.com>