Re: Question about Manipulate

*To*: mathgroup at smc.vnet.net*Subject*: [mg122782] Re: Question about Manipulate*From*: Armand Tamzarian <mike.honeychurch at gmail.com>*Date*: Thu, 10 Nov 2011 06:54:10 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <j9domc$b5c$1@smc.vnet.net>

On Nov 9, 10:37 pm, "mail... at gmail.com" <mail... 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? your a and b within the Manipulate are not the global a and b you have used outside of the manipulate in your definition of f. That is why it is failing. In this particular case the syntax styling gives a heads up that they are different beasts. Mike