Re: a question about plot a list of functions.

*To*: mathgroup at smc.vnet.net*Subject*: [mg58206] Re: [mg58203] a question about plot a list of functions.*From*: "Caffa Vittorio Dr." <Caffa at iabg.de>*Date*: Wed, 22 Jun 2005 03:04:09 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Change Plot[y, {x, 0, 10 Pi}]; To Plot[Evaluate[y], {x, 0, 10 Pi}]; Cheers, Vittorio >-----Original Message----- >From: Zhou Jiang [mailto:jiangzhou_yz at yahoo.com] To: mathgroup at smc.vnet.net >Sent: Wednesday, June 22, 2005 7:56 AM >Subject: [mg58206] [mg58203] a question about plot a list of functions. > > >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. >