documentclass[10pt]{article}
usepackage{pgf,tikz,pgfplots}
pgfplotsset{compat=1.16}
% usepackage{mathrsfs}
usetikzlibrary{arrows}
pagestyle{empty}
begin{document}
definecolor{ffqqqq}{rgb}{1.,0.,0.}
definecolor{qqqqff}{rgb}{0.,0.,1.}
definecolor{qqwuqq}{rgb}{0.,0.39215686274509803,0.}
begin{tikzpicture}[line cap=round,line join=round,>=triangle 45,x=1.0cm,y=1.0cm]
begin{axis}[
x=1.0cm,y=1.0cm,
axis lines=middle,
ymajorgrids=true,
xmajorgrids=true,
xmin=-2.118707736780596,
xmax=5.255760268305019,
ymin=-4.168187134916317,
ymax=0.14792878906557064,
xtick={-2.0,-1.0,...,5.0},
ytick={-4.0,-3.0,...,0.0},]
clip(-2.118707736780596,-4.168187134916317) rectangle (5.255760268305019,0.14792878906557064);
% draw[line width=4.pt] (7.811006812257485,-1.2289916284010438) -- (10.458930692000973,-1.2289916284010438);
% draw[line width=4.pt] (7.78452757346005,-2.261681941501005) -- (10.432451453203537,-2.261681941501005);
% draw[line width=4.pt] (7.7977671928587675,-1.7453367849510244) -- (10.445691072602255,-1.7453367849510244);
addplot[line width=2.pt,color=qqwuqq,smooth,samples=100,domain=-2.118707736780596:1]
{0-2.0/3.0*3.141592653589793*0.05*10.2*(3.0*1.0^(2.0)-(x)^(2.0))};
addplot[line width=2.pt,color=qqqqff,smooth,samples=100,domain=1:5.255760268305019]
{0-4.0/3.0*3.141592653589793*0.05*10.2*1.0/(x)*1.0^(3.0)};
draw [line width=1.2pt,dash pattern=on 2pt off 2pt] (1.,-4.168187134916317) -- (1.,0.14792878906557064);
addplot[line width=2.pt,color=ffqqqq,domain=-2.118707736780596:5.255760268305019]
{(-4.272566012175239--2.1362830077341797*x)/1.};
begin{scriptsize}
draw[color=black] (9.187927229724098,-0.9178605725311839) node {$a = 1$};
draw[color=black] (8.062559580833117,-1.9505508856311446) node {$G = 0.05$};
draw[color=black] (8.76425940896514,-1.4342057290811645) node {$rho = 10.2$};
draw[color=qqwuqq] (-1.8539153488062472,-0.7589851397465746) node {$f$};
draw[color=qqqqff] (0.5027369041654571,-6.518219578188664) node {$g$};
draw[color=black] (1.2044367322974814,-1.9902697438272972) node {$A$};
draw[color=ffqqqq] (1.9061365604295057,-0.6001097069619652) node {$i$};
end{scriptsize}
end{axis}
end{tikzpicture}


begin{tikzpicture}[line cap=round,line join=round,>=triangle 45,x=1.0cm,y=1.0cm]
begin{axis}[
x=1.0cm,y=1.0cm,
axis lines=middle,
ymajorgrids=true,
xmajorgrids=true,
xmin=-2.118707736780596,
xmax=5.255760268305019,
ymin=-4.168187134916317,
ymax=0.14792878906557064,
xtick={-2.0,-1.0,...,5.0},
ytick={-4.0,-3.0,...,0.0},]
clip(-2.118707736780596,-4.168187134916317) rectangle (5.255760268305019,0.14792878906557064);
% draw[line width=4.pt] (7.811006812257485,-1.2289916284010438) -- (10.458930692000973,-1.2289916284010438);
% draw[line width=4.pt] (7.78452757346005,-2.261681941501005) -- (10.432451453203537,-2.261681941501005);
% draw[line width=4.pt] (7.7977671928587675,-1.7453367849510244) -- (10.445691072602255,-1.7453367849510244);
addplot[line width=2.pt,color=qqqqff,smooth,samples=100,domain=1:5.255760268305019]
{0-4.0/3.0*3.141592653589793*0.05*10.2*1.0/(x)*1.0^(3.0)};
draw [line width=1.2pt,dash pattern=on 2pt off 2pt] (1.,-4.168187134916317) -- (1.,0.14792878906557064);
addplot[line width=2.pt,color=qqwuqq,domain=-2.118707736780596:1]
{(-4.272566012175239-2.1362830077341797*(x-2))/1.};
begin{scriptsize}
draw[color=black] (9.187927229724098,-0.9178605725311839) node {$a = 1$};
draw[color=black] (8.062559580833117,-1.9505508856311446) node {$G = 0.05$};
draw[color=black] (8.76425940896514,-1.4342057290811645) node {$rho = 10.2$};
draw[color=qqwuqq] (-1.8539153488062472,-0.7589851397465746) node {$f$};
draw[color=qqqqff] (0.5027369041654571,-6.518219578188664) node {$g$};
draw[color=black] (1.2044367322974814,-1.9902697438272972) node {$A$};
end{scriptsize}
end{axis}
end{tikzpicture}
end{document}