[?] Plot an asymptote with conditions?

Questions
1

I want to place several graphs in the same Show with specified range beforehand. With these conditions I can not graph of the defined function within the specified range. There is an asymptote there. What can I do?

f[x_] := (x)/(Sqrt[x^2 - 4]);

miPlot = Plot[f[x], {x, -10, 10}];

asintotai =   Graphics[{Thickness[0.001], Dashed, Line[{{-2, -20}, {-2, 20}}]}];

asintotad =    Graphics[{Thickness[0.001], Dashed, Line[{{2, -20}, {2, 20}}]}];

Show[ miPlot, asintotai, asintotad, PlotRange -> {{-10, 10}, {-20, 20}} ]
2

You must give the PlotRange to miPlot. With Show it’s too late, the clipping was already done:

miPlot = Plot[f[x], {x, -10, 10}, PlotRange -> All];
3

Thank you Gianluca. I will sleep well tonight.

:slight_smile: