Re: Plotting in a dynamic environment.

*To*: mathgroup at smc.vnet.net*Subject*: [mg99636] Re: Plotting in a dynamic environment.*From*: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>*Date*: Sun, 10 May 2009 05:13:52 -0400 (EDT)*References*: <gu3at0$t8t$1@smc.vnet.net>

Hi Marcel, You should make the dependence of myfun on x and t explicit. That's always a good idea, but for Manipulate to work it should be able to 'see' that changing t does something to the object that is the focus of the Manipulate construct. In addition, the Evaluate you used is not necessary here. This works: myfun[x_, t_] := x^2 + 3 t x; t = 1; Plot[myfun[x, t], {x, 0, 2}] Clear[t] Manipulate[myfun[x, t]] {x, 1, 2}, {{t, 1}, 0, 10}] Manipulate[Plot[myfun[x, t], {x, 1, 2}], {{t, 1}, 0, 10}] Cheers -- Sjoerd On May 9, 9:21 am, mgoic <mag... at gmail.com> wrote: > Hi everyone, > > I am having problems when trying to plot an expression in a Dynamic > model using manipulate tool. For example, in this simple code I can > plot the function (first plot), I can evaluate its value in a > manipulate environment (second plot), but when trying to plot in a > dynamic environment I just get empty axis (third plot). > > myfun = x^2 + 3 t x ; > t = 1; > Plot[myfun, {x, 0, 2}] > Clear[t] > Manipulate[Evaluate[myfun], {x, 1, 2}, {{t, 1}, 0, 10}] > Manipulate[Plot[Evaluate[myfun], {x, 1, 2}], {{t, 1}, 0, 10}] > > Any idea of what I am doing wrong? I will really appreciate any > guidance. > > Regards, > Marcel Goic