Re: Simple Problem (I suppose...)

*To*: mathgroup at smc.vnet.net*Subject*: [mg22118] Re: Simple Problem (I suppose...)*From*: "David Bailey" <db at salford-software.com>*Date*: Wed, 16 Feb 2000 02:34:34 -0500 (EST)*Organization*: University of Salford, Salford, Manchester, UK*References*: <888a2i$c6a@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Andreas Kallmeyer <kallmeyer at bigfoot.com> wrote in message news:888a2i$c6a at smc.vnet.net... > Hi! > > I just got Mathematica 4 and when I try such easy calculations as below > and then I can't plot the result.... WHY?? I really have no clue. > > Thanks, > > Andreas. > > Here my text is clipped: > " > In[1]:= > Remove["Global'*"] > > Remove::"rmnsm": "There are no symbols matching \"\!\(\"Global'*\"\)\"." > > In[2]:= > \!\(f[\(x\_-\)] := \ x\^5 + x\^4 + x\^2\) > > In[3]:= > Plot[f[x], {x, -10, 10}]; > > Plot::"plnr": "\!\(f[x]\) is not a machine-size real number at \!\(x\) = > \ > \!\(-9.999999166666667`\)." > > Plot::"plnr": "\!\(f[x]\) is not a machine-size real number at \!\(x\) = > \ > \!\(-9.188660168541684`\)." > > In[4]:= > \!\(f2[\(x\_-\)]\ = \ \[PartialD]\_x f[x]\) > > Out[4]= > \!\(\* > RowBox[{ > SuperscriptBox["f", "\[Prime]", > MultilineFunction->None], "[", "x", "]"}]\) > > In[5]:= > ?f2 > > In[6]:= > \!\(f2[x]\ = \ \[PartialD]\_x f[x]\) > > Out[6]= > \!\(\* > RowBox[{ > SuperscriptBox["f", "\[Prime]", > MultilineFunction->None], "[", "x", "]"}]\) > " > I think the problem here is that rather than f[x_] you wrote the '_' character as a subscript of x. BTW, it is better to convert information to InputForm via the Cell>Convert To menu item before clipping it into an email. Indeed, had you done this, the mistake would probably have become obvious. David Bailey Salford Software