La alternativa gratuita a Overleaf

\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}[
  grow=right, level distance=2.8cm,
  level 1/.style={sibling distance=2.7cm},
  level 2/.style={sibling distance=1.4cm},
  every node/.style={font=\small},
  edge from parent/.style={draw, thick}
]
\node[inner sep=0pt] {}
  child { node {$A_3$}
    child { node {$\overline{S}$} edge from parent node[midway, yshift=-7pt, font=\scriptsize] {$0.03$} }
    child { node {$S$} edge from parent node[midway, yshift=7pt, font=\scriptsize] {$0.97$} }
   }
  child { node {$A_2$}
    child { node {$\overline{S}$} edge from parent node[midway, yshift=-7pt, font=\scriptsize] {$\cdots$} }
    child { node {$S$} edge from parent node[midway, yshift=7pt, font=\scriptsize] {$0.13$} }
   edge from parent node[midway, yshift=-7pt, font=\scriptsize] {$0.3$} }
  child { node {$A_1$}
    child { node {$\overline{S}$} edge from parent node[midway, yshift=-7pt, font=\scriptsize] {$\cdots$} }
    child { node {$S$} edge from parent node[midway, yshift=7pt, font=\scriptsize] {$0.54$} }
   edge from parent node[midway, yshift=7pt, font=\scriptsize] {$0.1$} }
;
\end{tikzpicture}
\end{document}

\documentclass[border=10pt]{standalone}
\usepackage{tkz-tab}
\begin{document}
\begin{center}
\begin{tikzpicture}
\tikzset{double distance=3pt,dashed/.style={},dotted/.style={}}
\tkzTabInit{{$x$} / 1, {$f'(x)$} / 1, {$f(x)$} / 1.5}%
            {{$-\infty$}, {$10$}, {$+\infty$}}
\tkzTabLine{d, +, t, -,}
\tkzTabVar{D-/ /{$-\infty$}, +/{$0$}, -/{$0$}}
\end{tikzpicture}
\end{center}
\end{document}

\documentclass{article}
\usepackage[most]{tcolorbox}

\definecolor{theoreme-bg}{HTML}{EFF6FF}
\definecolor{theoreme-text}{HTML}{1F2937}
\definecolor{theoreme-frame}{HTML}{3B82F6}
\definecolor{theoreme-title-bg}{HTML}{3B82F6}
\definecolor{theoreme-title-fg}{HTML}{FFFFFF}

\newtcolorbox{theoreme}{%
  enhanced,
  breakable,
  colback=theoreme-bg,
  colupper=theoreme-text,
  colframe=theoreme-frame,
  colbacktitle=theoreme-title-bg,
  coltitle=theoreme-title-fg,
  fonttitle=\bfseries,
  boxrule=1pt,
  arc=3pt,
  top=2mm, bottom=2mm,
  title=Theorema Pythagorae,
}
\begin{document}
\begin{theoreme}
In triangulo rectangulo, quadratum hypotenusae aequatur summae
quadratorum laterum: $a^2 + b^2 = c^2$.
\end{theoreme}
\end{document}

\documentclass{article}

\usepackage{booktabs}
\usepackage[table]{xcolor}
\usepackage{array}
\usepackage{amsmath}
\usepackage{amssymb}

\definecolor{cellBBF7D0}{HTML}{BBF7D0}
\definecolor{cellBFDBFE}{HTML}{BFDBFE}

\renewcommand{\arraystretch}{1.2}
\setlength{\tabcolsep}{8pt}
\setlength{\aboverulesep}{0pt}
\setlength{\belowrulesep}{0pt}

\begin{document}
{\setlength{\extrarowheight}{6pt}
\begin{tabular}{| c | c | c | c | c | c | c |}
  \toprule
  \rowcolor{cellBBF7D0}
  $x$ & $0$ & $1$ & $2$ & 3 & 4 & 5 \\[6pt]
  \midrule
  \cellcolor{cellBBF7D0}$f(x)$ & $2.1$ & $5.6$ & $\dfrac{3}{8}$ & $\sqrt{7}$ & $7.9$ & $100$ \\[6pt]
  \midrule
  \cellcolor{cellBBF7D0}$g(x)$ & $-1$ & $1$ & $-1$ & $1$ & $-1$ & $1$ \\[6pt]
  \midrule
  ~ & ~ & \multicolumn{3}{|c|}{\cellcolor{cellBFDBFE}~} & ~ & ~ \\[6pt]
  \cmidrule{1-2}
  \cmidrule{6-7}
  ~ & ~ & \multicolumn{3}{|c|}{\cellcolor{cellBFDBFE}TITLE} & ~ & ~ \\[6pt]
  \cmidrule{1-2}
  \cmidrule{6-7}
  ~ & ~ & \multicolumn{3}{|c|}{\cellcolor{cellBFDBFE}} & ~ & ~ \\[6pt]
  \bottomrule
\end{tabular}
}
\end{document}

\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{angles, quotes}
\begin{document}
\begin{tikzpicture}
  \coordinate (A) at (3,0);
  \coordinate (O) at (0,0);
  \coordinate (B) at (60:3);
  \draw (O) circle (3);
  \draw (O) -- (A) node[midway, below] {$r$};
  \draw (O) -- (B);
  \pic [draw, "$\theta$", angle radius=0.6cm,
        angle eccentricity=1.5] {angle=A--O--B};
  \fill (O) circle (2pt) node[below left] {$O$};
\end{tikzpicture}
\end{document}