[?] Use Plot Labels for Parametric curves?

Questions
1

Below is a code snippet to plot a handful of curves with some plot labels. For some reason only the first label is used and not the other four. What am I missing here? I’ve successfully used PlotLabels for parametric curves before but they seem to fail me here. Got any ideas??:

lmt=10

qq[zets_]=1/Sqrt[1+zets^2]^3

zets[rr_,eps_,eta_]=eps (1-rr^2) (1+eta (1+rr^2))

demcurves=Array[qq[zets[rr,2 #/lmt,0]]&,lmt/2]

Plot[demcurves,{rr,0,1}]

demlabels = Map[ToString,Array[qqzz[N[2/lmt]#]&,lmt/2]]

Plot[demcurves,{rr,0,1},PlotLabels -> Placed[demlabels,Left]]
2

Your code does not run, so here I am just guessing. The labels may be superimposed. Try placing them where the curves are far from each other, instead of Left.

3

Gianluca,

Thank you for your response. Yes, I see that the online code does not work. The online definition of zets is wrong. On the left-hand-side of the definition of zets, rr must be replaced with rr_ and eps must be replaced by eps_. (The online editor omits the _ and I am unaware of what escape character to use to prevent its removal.)

If you correct the definition of zets and run the code you’ll see what my problem is.
Tony

4

When I run corrected code on version 11.1.1.0 on Win 7 x64 it produces the expected output, as seen below.
In the future, please put code in code bocks as noted in the group rules.

lmt=10;
qq[zets_]=1/Sqrt[1+zets^2]^3;
zets[rr_,eps_,eta_]=eps(1-rr^2) (1+eta (1+rr^2));
demcurves=Array[qq[zets[rr,2 #/lmt,0]]&,lmt/2];
Plot[demcurves,{rr,0,1}];
demlabels=Map[ToString,Array[qqzz[N[2/lmt]#]&,lmt/2]];
Plot[demcurves,{rr,0,1},PlotLabels->Placed[demlabels,Left]]

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