`\begin{tikzpicture}[font=\small]
\begin{axis} [width=\textwidth,
axis lines=middle,
xmin=-5,xmax=5,ymin=-15,ymax=15,
enlargelimits,
xtick={-5,…,5},
ytick={-4},
xlabel=$x$,
ylabel=$y$]
\addplot [domain=-6:6, samples=600,unbounded coords=jump,smooth,very thick,blue] {(4-x*x)/(x-1)};
\pattern [pattern= north east lines, pattern color=blue!75!white] (axis cs:1,-18) rectangle (axis cs:2,0);
\pattern [pattern= north east lines, pattern color=blue!75!white] (axis cs:2,0) rectangle (axis cs:18,18);
\pattern [pattern= north east lines, pattern color=blue!75!white] (axis cs:-2,0) rectangle (axis cs:1,18);
\pattern [pattern= north east lines, pattern color=blue!75!white] (axis cs:-2,0) rectangle (axis cs:-18,-18);
\draw [blue,thick,dashed] (axis cs:1,-20) — (axis cs:1,20);
\draw [blue,thick,dashed] (axis cs:2,-20) — (axis cs:2,20);
\draw [blue,thick,dashed] (axis cs:-2,-20) — (axis cs:-2,20);
\draw (axis cs:1,0) [blue,fill=white,very thick] circle (2.0pt);
\draw (axis cs:2,0) [blue,fill=blue,very thick] circle (2.0pt);
\draw (axis cs:-2,0) [blue,fill=blue,very thick] circle (2.0pt);
\draw (axis cs:0,-4) [blue,fill=blue,very thick] circle (2.0pt);
\end{axis}
\end{tikzpicture}
`
Perché l’opzione “unbounded coords=jump” non funziona?
In generale, faccio errori nel codice precedente?