Oi Renato,
Muito obrigada por tentar me ajudar.
Meu preambulo é este:
\documentclass [a4paper,12pt]{report}
%% ---------------------------------------------------------------------------
\usepackage{graphics}
\usepackage{graphicx}
\usepackage[latin1]{inputenc}
\usepackage[portuges]{babel}
%\usepackage{comment}
%\usepackage{amssymb}
\usepackage{amsfonts,amsmath, amsthm, amssymb}
\usepackage{epsf}
%\usepackage{psfig}
%\usepackage{float}
%\usepackage{stmaryrd}
%\usepackage[ansinew]{inputenc}
%\usepackage{latexsym}
\usepackage{url}
% Pacote para gerar o cabecalho
\usepackage{fancyhdr}
\usepackage{makeidx}
\makeindex
% ---------------------------------------------------------------------------
\input{epsf}
\renewcommand\baselinestretch{1.6}
\textwidth 15 cm
%\setlength{\topmargin}{-1 cm} % corretos
%\setlength{\oddsidemargin}{.5 cm} % corretos
\setlength{\topmargin}{.4 cm} % corretos
\setlength{\oddsidemargin}{.8 cm}
\textheight 23.7 cm
\flushbottom
% ---------------------------------------------------------------------------
\newcommand\e{\varepsilon}
\newcommand\OO{\Omega}
\newcommand\LL{\mathcal{L}}
\newcommand\MM{\mathcal{M}}
% In this text tau represents a tensor.
% Using \taub we, automaticaly, add a bold face tau
\newcommand{\taub}{\mbox{\boldmath$\tau$}}
\newcommand{\phib}{\mbox{\boldmath$\phi$}}
\newcommand{\lambdab}{\mbox{\boldmath$\lambda$}}
\newcommand\ubb{\textbf{u}}
\newcommand\ut{\text{u}}
\newcommand\vbb{\textbf{v}}
\newcommand\fbb{\textbf{f}}
\newcommand\ft{\text{f}}
\newcommand\wbb{\textbf{w}}
\newcommand\Obb{\textbf{0}}
\newcommand\ebb{\textbf{e}}
\newcommand\rbb{\textbf{r}}
\newcommand\xbb{\textbf{x}}
%\renewcommand{\thesubsection}{\alph{subsection}.}
%\renewcommand{\thesubsubsection}{\roman{subsubsection})}
%-----------------------------------------------------------------------------
%
%----------------------------------------------------------------------------
\newtheorem{lemma}{Lema}[chapter]
%\newtheorem{definicao}[lemma]{Defini\c c\~ao}
%\newtheorem{teorema}[lemma]{Teorema}
%\newtheorem{proposicao}[lemma]{Proposi\c c\~ao}
\newtheorem{obs}[lemma]{Observa\c c\~ao}
%\newtheorem{corolario}[lemma]{Corol\'ario}
%\newenvironment{prova}{\smallskip \noindent{\bf Prova}: }
%{\hfill $\Box$\hspace{1in}\medskip}
%----------------------------------------------------------------------------
%
http://72.14.207.104/search?q=cache:6roYcZYEUgoJ:www-h.eng.cam.ac.uk/help/tpl/
%textprocessing/float_hint.html+figures+in+latex&hl=pt-BR
%
\renewcommand\floatpagefraction{.9}
\renewcommand\topfraction{.9}
\renewcommand\bottomfraction{.9}
\renewcommand\textfraction{.1}
\renewcommand{\appendixname}{Annex}
\setcounter{totalnumber}{50}
\setcounter{topnumber}{50}
\setcounter{bottomnumber}{50}
%
%
% Documento Principal
%
\begin{document}
--
Ruth da Silva BrumLicenciada em Matemática
Especialista em educação em ciências e tecnologias
Mestranda do Programa de Pós Graduação em Modelagem Computacional