\documentclass[a4paper,12pt]{article}

\usepackage[hypcap]{caption}
\usepackage{amssymb}
\usepackage{mathtools}
\usepackage{times}
\usepackage{fancyhdr}
\usepackage[pdftex]{graphics}
\usepackage{latexsym}
\usepackage{amsmath,amsthm}
\usepackage[utf8x]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[brazilian]{babel}
\usepackage{ifthen}
\usepackage{xifthen}


\usepackage{listings}
\lstset{ 
  basicstyle=\footnotesize,        % the size of the fonts that are used for the code
  breakatwhitespace=false,         % sets if automatic breaks should only happen at whitespace
  %keywordstyle=\color{blue},       % keyword style
  language=Tex,                    % the language of the code
}
\usepackage{cancel}
\usepackage{enumerate}
\usepackage{geometry}
\geometry{
  a4paper,
  paperwidth=21cm,
  paperheight=35cm,
  headheight=2cm,
  total=17cm,
  left=3cm,
  right=3cm,
  top=3cm,
  bottom=3cm,
}
\usepackage{float}

%\setlength{\topmargin}{0cm}
%\setlength{\headsep}{1cm}
%\setlength{\topsep}{0cm}
%%\setlength{\topskip}{0cm}
%\setlength{\footskip}{1cm}
%%\setlength{\headheight}{2cm}
%%\addtolength{\textwidth}{4cm}
%%\setlength{\hoffset}{-2cm}

%%\setlength{\voffset}{-2cm}
%\addtolength{\textheight}{8cm}

\setlength{\parindent}{0cm}
%\setlength{\evensidemargin}{1cm}
%\setlength{\oddsidemargin}{1cm}
%\setlength{\marginparwidth}{0cm}
%\setlength{\marginparsep}{0cm}
%\setlength{\linewidth}{0.05cm}
%\setlength{\arrayrulewidth}{0.1pt}
%\setlength{\doublerulesep}{0cm}

\DeclareMathOperator{\Arctan}{Arctan}
\DeclareMathOperator{\Arcsin}{Arcsin}
\DeclareMathOperator{\Artanh}{Artanh}
\DeclareMathOperator{\Real}{Re}
\DeclareMathOperator{\Imag}{Im}
\DeclareMathOperator{\Det}{Det}


\newtheorem{Axiom}{Axioma}
\newtheorem{Theorem}{Teorema}[section]
\newtheorem
    {Definition}
    [Theorem]
    {Definição}
\newtheorem
    {Proposition}
    [Theorem]
    {Proposição}
\newtheorem
    {Corollary}
    [Theorem]
    {Corolário}
\newtheorem
    {Lemma}
    [Theorem]
    {Lema}

\newtheorem
    {Comment}
    [Theorem]
    {Comment}

%Put your favourite logos here - or use for something else
%\lhead{\includegraphics*{/var/www/icons/ufg2.png}}
%\rhead{\includegraphics*{/var/www/icons/SAdE_owl.png}}

\chead{
   \textbf{
	  \begin{Large}Dr. Ole Peter Smith\end{Large}\\
          Instituto de Matem\'atica e Estat\'{\i}stica\\
          Universidade Federal de Goi\'as\\
      \begin{small}ole@ufg.br - http://olepeter.ime.ufg.br\end{small}
   }
}

\lfoot{\large{$\mu$}\small{$\alpha\tau\epsilon\mu\alpha\tau\iota\kappa\alpha$\\
              \textbf{Made in \LaTeX}\\\today}}
\rfoot{\small{\textbf{
   \input{Ditado.txt}
}}}
\pagestyle{fancy}

\newcommand{\Vector}[1]{\underline{\mathbf{#1}}}
\newcommand{\Matrix}[1]{\underline{\underline{{\mathbf{#1}}}}}

\newcommand{\Result}[1]{\underline{\underline{~~#1~~}}}
\newcommand{\Wronsky}[2]
{
   \left|\begin{array}{cc}
      #1(t)  & #2(t)\\
      #1'(t) & #2'(t)
   \end{array}\right|
}
\newcommand{\IntegralZero}[2]
{
   \int \frac{1}{#1(t)^2} e^{-#2(t) } dt
}
\newcommand{\Integral}[3]
{
   \int \frac{#1(t) #2(t) }{#3(t)} dt
}
\usepackage{pgfplots}
\pgfplotsset{compat=1.8}
\usepackage{tikz}
\usepackage{tkz-euclide}
\usetkzobj{all}
\usetikzlibrary
    {
      shapes.geometric,
      arrows,
      calc,
      intersections,
      arrows.meta,
      decorations.markings,
      positioning,
      math,
      angles,
      quotes,
      patterns,
      backgrounds,
      fillbetween
    }

\makeatletter
\newcommand{\gettikzxy}[3]{%
  \tikz@scan@one@point\pgfutil@firstofone#1\relax
  \edef#2{\the\pgf@x}%
  \edef#3{\the\pgf@y}%
}
\makeatother



\tikzstyle{arrow} = [thick,-,>=stealth]
\tikzstyle{myarrow} = [thick,->,>=stealth]

\usepackage{scrextend}

\newcounter{Example}[section]
\newcommand{\Example}[2]{
   \stepcounter{Example}
   \label{item:\theExample}
   \small{\underline{\textit{Exemplo \thesection.\theExample:}} #1
     \begin{addmargin}[1em]{2em}% 1em left, 2em right
       #2
     \end{addmargin}
   }
}
\newcounter{Exercise}[section]
\newcommand{\Exercise}[2]{
   \stepcounter{Exercise}
   \label{item:\theExercise}
   \textbf{\thesection.\theExercise}
   #1
}

\begin{document}
  
