\documentclass[usenames,dvipsnames]{article}
\usepackage{pgfplots}
prima figura
codice prima figura
\begin{tikzpicture}
\begin{axis}[
axis equal image,
axis on top ,
axis x line=center,
axis y line=center,
xtick = \empty,
ytick = \empty,
axis equal image,
axis x line=center,
axis y line=center,
xmin = -2,
xmax = 3,
ymin = -2,
ymax = 3,
xlabel = {$x$},
ylabel = {$y$},
extra x ticks = {0},
extra x tick label = {$\hspace{0.4cm}0$},
y label style={anchor=north east}
]
\addplot[samples=100,domain=0:6, very thick,SkyBlue] {-{1/sqrt(3)}*x};
\addplot[dashed,samples=100,domain=-6:0,SkyBlue] {-1/sqrt(3)*x};
\addplot[samples=100,domain=0:6, very thick,red] {1/sqrt(3)*x};
\addplot[dashed,samples=100,domain=-6:0,red] {1/sqrt(3)*x};
\addplot[mark=*] coordinates {(1,0)} node[below right] {$A$};
\addplot[mark=*] coordinates {(2,-0.5)} node[below right] {$B$};
\draw (axis cs:0.8,0.7) node[rotate=0,red] {$\lambda$};
\draw (axis cs:0.7,-0.7) node[rotate=0,SkyBlue] {$-\lambda$};
\addplot[samples=100,domain=0.273861:0.316228,] {sqrt(1/10-x^2)};
\addplot[samples=100,domain=0.273861:0.316228,] {-sqrt(1/10-x^2)};
\draw (axis cs:0.45,0.12) node[rotate=0] {$\alpha$};
\draw (axis cs:0.45,-0.12) node[rotate=0] {$\alpha$};
\end{axis}
\end{tikzpicture}
seconda figura
codice seconda figura
\begin{tikzpicture}
\begin{axis}[
axis equal image,
axis on top ,
axis x line=center,
axis y line=center,
xtick = \empty,
ytick = \empty,
axis equal image,
axis x line=center,
axis y line=center,
xmin = -2,
xmax = 3,
ymin = -2,
ymax = 3,
xlabel = {$x$},
ylabel = {$y$},
extra x ticks = {0},
extra x tick label = {$\hspace{0.4cm}0$},
y label style={anchor=north east}
]
\addplot[dashed,samples=100,domain=-6:6] {-{1/sqrt(3)}*x};
\addplot[samples=100,domain=-4:4] {-1/sqrt(3)*x};
\addplot[samples=100,domain=-4:4] {1/sqrt(3)*x};
\addplot[dashed,samples=100,domain=-6:6] {1/sqrt(3)*x};
\addplot[mark=*,red] coordinates {(1,0)} node[below right] {$A$};
\addplot[mark=*,red] coordinates {(2,-0.5)} node[below right] {$B$};
\addplot[samples=100,domain=0.75:1] {-sqrt(3)*(x-1)};
\addplot[samples=100,domain=0.75:1] {sqrt(3)*(x-1)};
\addplot[samples=100,domain=1.2835:2] {-1/2-sqrt(3)*(x-2)};
\addplot[samples=100,domain=1.716506:2] {-1/2+sqrt(3)*(x-2)};
\draw (axis cs:1,1) node[rotate=30] {$y=1/(\sqrt{3})x$};
\draw (axis cs:1,-1) node[rotate=-30] {$y=-1/(\sqrt{3})x$};
\draw (axis cs:1,0.345) node[rotate=0] {$r_1$};
\draw (axis cs:1,-0.4) node[rotate=0] {$r_2$};
\draw (axis cs:1,-1) node[rotate=-30] {$y=-1/(\sqrt{3})x$};
\draw (axis cs:1.8,0.2) node[rotate=0] {$r_3$};
\draw (axis cs:2 ,-0.9) node[rotate=0] {$r_4$};
\draw (axis cs:2,-0.9) node[rotate=0] {$r_4$};
\end{axis}
\end{tikzpicture}
terza figura
codice terza figura
\begin{tikzpicture}
\begin{axis}[
xtick = \empty,
axis equal image,
ytick = \empty,
axis equal image,
axis x line=center,
axis y line=center,
xmin = -5,
xmax =8,
ymin = 0,
ymax = 18,
xlabel = {$x$},
ylabel = {$y$},
extra x ticks = {0},
extra x tick label = {$\hspace{-0.6cm}0$},
y label style={anchor=north east}
]
\addplot[very thick,samples=100,domain=-2:6,
green] {x^2-4*x+4};
\addplot[mark=*] coordinates {(2,0)} node[above right] {$V$};
\addplot[mark=*] coordinates {(17/4,81/16)} node[above right] {$A$};
\end{axis}
\end{tikzpicture}
quarta figura
codice quarta figura
\begin{tikzpicture}
\begin{axis}[
xtick = \empty,
axis equal image,
ytick = \empty,
axis equal image,
axis x line=center,
axis y line=center,
xmin = -5,
xmax =8,
ymin = -5,
ymax = 10,
xlabel = {$x$},
ylabel = {$y$},
extra x ticks = {0},
extra x tick label = {$\hspace{-0.6cm}0$},
y label style={anchor=north east}
]
\addplot[samples=100,domain=-2:6,
green] {x^2-4*x+4};
\addplot[mark=*] coordinates {(2,0)} node[above right] {$V$};
\addplot[mark=*] coordinates {(17/4,81/16)} node[above right] {$A$};
\addplot[samples=100,domain=-6:40,
red] {1/4*x+4};
\addplot[samples=100,domain=-6:40] {-4*x+4};
\addplot[mark=*] coordinates {(0,4)} node[above right] {$B$};
\end{axis}
\end{tikzpicture}
quinta figura
codice quinta figura
\begin{tikzpicture}
\begin{axis}[
xtick = \empty,
axis equal image,
ytick = \empty,
axis equal image,
axis x line=center,
axis y line=center,
xmin = -5,
xmax =8,
ymin = 0,
ymax = 20,
xlabel = {$x$},
ylabel = {$y$},
extra x ticks = {0},
extra x tick label = {$\hspace{-0.6cm}0$},
y label style={anchor=north east}
]
\addplot[samples=100,domain=-2:6,
green] {x^2-4*x+4};
\addplot[mark=*] coordinates {(2,0)} node[above right] {$V$};
\addplot[mark=*] coordinates {(21/4,169/16)} node[above right] {$D$};
\addplot[samples=100,domain=-6:40,
red] {1/4*x+37/4};
\addplot[mark=*] coordinates {(-1,9)} node[above right] {$C$};
\end{axis}
\end{tikzpicture}