In[]:=
Legended[GraphicsColumn[{Plot[Cos[x],{x,0,4π},Ticks->{None,Automatic},GridLines->{Range[0,4π,π/2],None},GridLinesStyle->Directive[Gray,Dashed],AxesLabel->{f[x],None},Epilog->{PointSize[.01],Point[{#,0}]&/@Range[π/2,4π,π]}],Plot[-Sin[x],{x,0,4π},Ticks->{None,Automatic},GridLines->{Range[0,4π,π/2],None},GridLinesStyle->Directive[Gray,Dashed],AxesLabel->{f'[x],None},Epilog->{PointSize[.015],Point[{#,0}]&/@Range[0,4π,π]}],Plot[-Cos[x],{x,0,4π},Ticks->{Range[0,4π,π/2],Automatic},GridLines->{Range[0,4π,π/2],None},GridLinesStyle->Directive[Gray,Dashed],AxesLabel->{f''[x],None},Epilog->{PointSize[.02],Point[{#,0}]&/@Range[π/2,4π,π]}]},Spacings->0],PointLegend[{Black,Black,Black},{"Rest Position","Critical Point","Inflection Point"},LegendMarkerSize->{8,12,16}]]
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