Re: Don't understand Plot behavior

*To*: mathgroup at smc.vnet.net*Subject*: [mg39994] Re: [mg39971] Don't understand Plot behavior*From*: Ken Levasseur <klevasseur at mac.com>*Date*: Fri, 14 Mar 2003 04:45:32 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Alain: Evaluate needs to be at the top level of the first argument of plot to have the effect that it has in your first example. I had defined f=#^2& earlier. This is what happens in your first example In[11]:= Hold[Evaluate[f[t]]] Out[11]= Hold[t^2] Now the second: In[12]:= Hold[{Evaluate[f[t]], 0}] Out[12]= Hold[{Evaluate[f[t]], 0}] If you rearrange the the expression, you get what you want: In[13]:= Hold[Evaluate[{f[t], 0}]] Out[13]= Hold[{t^2, 0}] Ken Levasseur UMass Lowell > From: Alain Cochard <al2 at noos.fr> To: mathgroup at smc.vnet.net > Date: Thu, 13 Mar 2003 03:03:58 -0500 (EST) > To: mathgroup at smc.vnet.net > Subject: [mg39994] [mg39971] Don't understand Plot behavior > > > In[1]:= f[t_]:= D[t , t] > > In[2]:= Plot[Evaluate[f[t]] , {t, 0, 1}] > > Out[2]= -Graphics- [The plot is fine] > > In[3]:= Plot[{Evaluate[f[t]],0} , {t, 0, 1}] > > -8 > General::ivar: 4.16667 10 is not a valid variable. > > [...] > > General::stop: Further output of General::ivar > will be suppressed during this calculation. > > Plot::plnr: Evaluate[f[t]] is not a machine-size real number at t = > -8 > 4.16667 10 . > > [...] > > General::stop: Further output of Plot::plnr > will be suppressed during this calculation. > > Out[3]= -Graphics- [The plot just shows the axes] > > In[4]:= harhar=Evaluate[f[t]]; Plot[{harhar,0} , {t, 0, 1}] > > Out[4]= -Graphics- [The plot is fine] > > In[5]:= $Version > > Out[5]= 4.1 for Sun Solaris (November 8, 2000) > > > Is this behavior normal? Thx in advance. > > Alain Cochard > al2 at noos.fr > >