\begin{gnuplot}[terminal=pdf,terminaloptions={font ",10" linewidth 2}]
	unset border
    set  nogrid
            set lmargin at screen 0
		set rmargin at screen 1
		set bmargin at screen 0
		set tmargin at screen 1
	set yrange [-12:-1]
	set xrange [-4:4]
	set size 5/5.
	set key center top reverse Left
	set xzeroaxis
	set yzeroaxis
	set xtics axis out scale 0.5
	set ytics axis
	plot(sqrt(4-x)/(sqrt(12+x)-4)) lt rgb "#FFAA00"
\end{gnuplot}