Re: a question about plot a list of functions.

*To*: mathgroup at smc.vnet.net*Subject*: [mg58214] Re: a question about plot a list of functions.*From*: dh <dh at metrohm.ch>*Date*: Thu, 23 Jun 2005 05:33:50 -0400 (EDT)*References*: <d9av6m$vn$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hi Zhou, Plot does not evaluate its arguments automatically (Attribute: HoldAll). Therefore, you must use Evaluate: Plot[Evaluate[y],{x,0,10Pi}] sincerely, Daniel Zhou Jiang wrote: > I defined a function as > > K=(2 r/(1-r^2))^2; > y=1/(1+K (Sin[x])^2); > y=y/.{r->{0.2,0.9,0.995}} > > Now the result is a list. > I want to plot y vs. x in one figure and I did the following > > Plot[y, {x, 0, 10 Pi}]; > > But Mathematica gave me an error. > I changed it to > > Plot[{y[[1]], y[[2]], y[[3]]}, {x, 0, 10 Pi}]; > > Mathematica gave me a correct plot. Can anyone give me some idea why the error message is given by Mathematica since y is a list and nothing is diffrent from {y[[1]], y[[2]], y[[3]]}? > > Thanks. > >