Prima figura
codice prima figura
\begin{tikzpicture}
\begin{axis}[
width = 0.7\textwidth,
height = 0.7\textwidth,
xtick = \empty,
ytick = \empty,
axis on top,
axis equal image,
axis x line=center,
axis y line=center,
xmin = -3,
xmax = 3,
ymin = -3,
ymax = 3,
xlabel = {$x$},
ylabel = {$y$},
extra x tick label = {$\hspace{0.4cm}O$},
disabledatascaling,
]
\draw (axis cs:2.1,0.5) node[rotate=0] [RoyalBlue]{$\partial A$};
\addplot[mark=*,very thick,RoyalBlue] coordinates {(1,1) (0,0) (1,-1)};
\addplot[mark=*,RoyalBlue] coordinates {(0,0)} node[below left] {$O$};
\addplot[mark=*,RoyalBlue] coordinates {(1,1)} node[above ] {$B$};
\addplot[mark=*,RoyalBlue] coordinates {(1,-1)} node[below ] {$C$};
\addplot[mark=*,RoyalBlue] coordinates {(-2,2)} node[below left ] {$(-2,2)$};
\addplot[mark=*,RoyalBlue] coordinates {(-2,-2)} node[above left ] {$(-2,-2)$};
\addplot[very thick,domain=1:2,RoyalBlue,name path=parabolasopra] {sqrt(2-x)};
\addplot[very thick,domain=1:2,RoyalBlue,name path=parabolasotto] {-sqrt(2-x)};
\addplot[very thick,domain=-2.5:1,dashed, RoyalBlue,name path=parabola sopra] {sqrt(2-x)};
\addplot[very thick,domain=-2.5:1, dashed,RoyalBlue,name path=parabola sotto] {-sqrt(2-x)};
\addplot[mark=*,dashed,very thick,RoyalBlue] coordinates { (0,0) (-2,-2)};
\addplot[mark=*,dashed,very thick,RoyalBlue] coordinates { (0,0) (-2,2)};
\addplot[dashed,very thick,RoyalBlue] coordinates { (1,1) (2,2)};
\addplot[dashed,very thick,RoyalBlue] coordinates { (1,-1) (2,-2)};
\addplot[very thick,domain=0:1,RoyalBlue,rotate=0,name path=retta 1] {x};
\addplot[very thick,domain=0:1,RoyalBlue,,name path=retta 2] {-x};
\end{axis}
\end{tikzpicture}
seconda figura
codice seconda figura
\begin{tikzpicture}
\begin{axis}[
width=0.5\textwidth,
disabledatascaling,
axis equal image,
axis x line=none,
axis y line=none,
xmin = 0,
xmax = 1,
ymin = 0,
ymax = 1,
clip=false,
]
\addplot[ultra thick,no marks,ProcessBlue] coordinates {(0,1) (0,0.4142) (0.4142,0) (1,0) (1,0.5858) (0.5858,1) (0,1)};
\addplot[no marks,thin] coordinates {(0,0) (1,0) (1,1) (0,1) (0,0)};
\addplot[no marks,very thick] coordinates {(0.5858,1) (1,1) (1,0.5858)};
\addplot[no marks,very thick] coordinates {(0,0.4142) (0,0) (0.4142,0)};
\addplot[mark=*] coordinates {(0,1)} node[above left] {$A$};
\addplot[mark=*] coordinates {(0.5858,1)} node[above] {$B$};
\addplot[mark=*] coordinates {(1,0.5858)} node[right] {$C$};
\addplot[mark=*] coordinates {(1,0)} node[below right] {$D$};
\addplot[mark=*] coordinates {(0.4142,0)} node[below] {$E$};
\addplot[mark=*] coordinates {(0,0.4142)} node[left] {$F$};
\addplot[mark=*] coordinates {(0,0)} node[below left] {$G$};
\addplot[mark=*] coordinates {(1,1)} node[above right] {$H$};
\end{axis}
\end{tikzpicture}
terza figura (tante figure simili)
codice figure numero tre in serie
\begin{tikzpicture}
\begin{axis}[
axis equal image,
scale=0.65,
axis x line=center,
axis y line=center,
xmin = -2.5,
xmax = 5.5,
ymin = -2,
ymax = 7.5,
xlabel = {$x$},
ylabel = {$y$},
xtick = \empty,
ytick = \empty,
extra x ticks = {0},
extra x tick label = {$\hspace{-0.6cm}O$},
colormap={bluered}{rgb255(0cm)=(0,0,255); rgb255(1cm)=(255,0,0)}
]
\addplot[very thick,samples=100,mesh,point meta=x] {(x-1)^2 - cos(pi*deg(x))};
\addplot[no marks] coordinates {(3,-1)} node[right] {\fbox{a}};
\end{axis}
\end{tikzpicture}
\begin{tikzpicture}
\begin{axis}[
axis equal image,
scale=0.65,
axis x line=center,
axis y line=center,
xmin = -2.5,
xmax = 5.5,
ymin = -2,
ymax = 7.5,
xlabel = {$x$},
ylabel = {$y$},
xtick = \empty,
ytick = \empty,
extra x ticks = {0},
extra x tick label = {$\hspace{-0.6cm}O$},
colormap={bluered}{rgb255(0cm)=(0,0,255); rgb255(1cm)=(255,0,0)}
]
\addplot[very thick,samples=100,mesh,point meta=x] {(x-1)^2 - 0.5*cos(2*pi*deg(x)) - 0.5};
\addplot[no marks] coordinates {(3,-1)} node[right] {\fbox{b}};
\end{axis}
\end{tikzpicture}
\begin{tikzpicture}
\begin{axis}[
axis equal image,
scale=0.65,
axis x line=center,
axis y line=center,
xmin = -2.5,
xmax = 5.5,
ymin = -2,
ymax = 7.5,
xlabel = {$x$},
ylabel = {$y$},
xtick = \empty,
ytick = \empty,
extra x ticks = {0},
extra x tick label = {$\hspace{-0.6cm}O$},
colormap={bluered}{rgb255(0cm)=(0,0,255); rgb255(1cm)=(255,0,0)}
]
\addplot[very thick,samples=100,mesh,point meta=x] {(x-1)^2 - 1};
\addplot[no marks] coordinates {(3,-1)} node[right] {\fbox{c}};
\end{axis}
\end{tikzpicture}
\begin{tikzpicture}
\begin{axis}[
axis equal image,
scale=0.65,
axis x line=center,
axis y line=center,
xmin = -2.5,
xmax = 5.5,
ymin = -2,
ymax = 7.5,
xlabel = {$x$},
ylabel = {$y$},
xtick = \empty,
ytick = \empty,
extra x ticks = {0},
extra x tick label = {$\hspace{0.6cm}O$},
colormap={bluered}{rgb255(0cm)=(0,0,255); rgb255(1cm)=(255,0,0)}
]
\addplot[very thick,samples=100,mesh,point meta=x] {x - cos(pi*deg(x))};
\addplot[no marks] coordinates {(3,-1)} node[right] {\fbox{d}};
\end{axis}
\end{tikzpicture}
\begin{tikzpicture}
\begin{axis}[
axis equal image,
scale=0.65,
axis x line=center,
axis y line=center,
xmin = -2.5,
xmax = 5.5,
ymin = -2,
ymax = 7.5,
xlabel = {$x$},
ylabel = {$y$},
xtick = \empty,
ytick = \empty,
extra x ticks = {0},
extra x tick label = {$\hspace{-0.6cm}O$},
colormap={bluered}{rgb255(0cm)=(0,0,255); rgb255(1cm)=(255,0,0)}
]
\addplot[very thick,samples=100,mesh,point meta=x] {(x-1)^2 + cos(pi*deg(x))};
\addplot[no marks] coordinates {(3,-1)} node[right] {\fbox{e}};
\end{axis}
!\end{tikzpicture}
\begin{tikzpicture}
\begin{axis}[
width=0.6\textwidth,
height=0.4\textwidth,
axis x line=center,
axis y line=center,
xmin = -0.95,
xmax = 2.95,
ymin = -1.5,
ymax = 1.5,
xlabel = {$x$},
ylabel = {$y$},
extra x ticks = {0},
extra x tick label = {$\hspace{-0.6cm}O$},
]
\addplot[very thick,samples=200,domain=-2:4,RedViolet] {(x-1)^2};
\addplot[very thick,samples=200,domain=-2:4,SeaGreen] {cos(pi*deg(x))};
\addplot[mark=diamond*,only marks,Yellow] coordinates {(0,1) (0.37,0.397) (1.63,0.397) (2,1)};
\addplot[RedViolet] coordinates {(1.1,1.35)} node[right] {$\scriptstyle y=(x-1)^2$};
\addplot[SeaGreen] coordinates {(1.2,-0.8)} node[right] {$\scriptstyle y=\cos(\pi x)$};
\end{axis}
\end{tikzpicture}
\begin{tikzpicture}
\begin{axis}[
width=0.6\textwidth,
height=0.4\textwidth,
axis x line=center,
axis y line=center,
xmin = -0.95,
xmax = 2.95,
ymin = -3.99,
ymax = 3.99,
xlabel = {$x$},
ylabel = {$y$},
extra x ticks = {0},
extra x tick label = {$\hspace{-0.6cm}O$},
]
\addplot[very thick,samples=200,domain=-2:4,RedViolet] {2*x-2};
\addplot[very thick,samples=200,domain=-2:4,SeaGreen] {-pi*sin(pi*deg(x))};
\addplot[thick,dotted] {pi};
\addplot[thick,dotted] {-pi};
\addplot[mark=diamond*,only marks,Yellow] coordinates {(0.176,-1.648) (1,0) (1.824,1.648)};
\addplot[no marks] coordinates {(2.0,pi)} node[above] {$\scriptstyle y=\pi$};
\addplot[no marks] coordinates {(1.5,-pi)} node[below] {$\scriptstyle y=-\pi$};
\addplot[RedViolet] coordinates {(2,1.8)} node[right] {$\scriptstyle y=2(x-1)$};
\addplot[SeaGreen] coordinates {(0.9,-2.5)} node[right] {$\scriptstyle y=-\pi\sin(\pi x)$};
\end{axis}
\end{tikzpicture}
Quarta figura
codice quarta figura
\begin{tikzpicture}
\begin{axis}[
axis equal image,
scale=1,
axis x line=center,
axis y line=center,
xmin = -2.5,
xmax = 2.5,
ymin = -1.5,
ymax = 1.5,
xlabel = {$x$},
ylabel = {$y$},
extra x ticks = {0},
extra x tick label = {$\hspace{-0.7cm}O$},
]
\addplot[very thick, domain=-180:180, samples=100, color=red] ({cos(x)},{sin(x)});
\addplot[very thick,samples=10,blue] {-x/2};
\addplot[very thick,samples=10,blue,dotted] {2*x};
\addplot[very thick,mark=*,only marks,PineGreen] coordinates {(0.4,-0.2) (0.7,0.4)} node[left] {$\phantom{O}P$};
\addplot[very thick,no marks,dotted,PineGreen] coordinates {(0.7,0.4) (0.4,-0.2)} node[below] {$H\phantom{|}$};
\addplot[very thick,mark=*,blue] coordinates {(0,0)} node {};
\addplot[only marks,blue] coordinates {(0.447,0.894)} node[right] {$\phantom{|}Q$};
\addplot[blue,no marks] coordinates {(-1.65,1.05)} node[rotate=-25.56] {$r$: $ax+by=0$};
\addplot[blue,no marks] coordinates {(-0.8,-1.2)} node {$s$};
\addplot[PineGreen,no marks] coordinates {(0.7,0.2)} node {$d$};
\end{axis}
\end{tikzpicture}