%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% LaTeX Example: Project Report
%
% Source: http://www.howtotex.com
%
% Feel free to distribute this example, but please keep the referral
% to howtotex.com
% Date: March 2011
%
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% How to use writeLaTeX:
%
% You edit the source code here on the left, and the preview on the
% right shows you the result within a few seconds.
%
% Bookmark this page and share the URL with your co-authors. They can
% edit at the same time!
%
% You can upload figures, bibliographies, custom classes and
% styles using the files menu.
%
% If you're new to LaTeX, the wikibook is a great place to start:
% http://en.wikibooks.org/wiki/LaTeX
%
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% Edit the title below to update the display in My Documents
% itle{Project Report}
%
%%% Preamble
documentclass[paper=a4, fontsize=11pt]{scrartcl}
usepackage[T1]{fontenc}
usepackage{fourier}
usepackage{setspace}
usepackage[english]{babel} % English language/hyphenation
usepackage[protrusion=true,expansion=true]{microtype}
usepackage{amsmath,amsfonts,amsthm} % Math packages
usepackage[pdftex]{graphicx}
usepackage{url}
%%% Custom sectioning
usepackage{sectsty}
allsectionsfont{centering
ormalfontscshape}
%%% Custom headers/footers (fancyhdr package)
usepackage{fancyhdr}
pagestyle{fancyplain}
fancyhead{} % No page header
fancyfoot[L]{} % Empty
fancyfoot[C]{} % Empty
fancyfoot[R]{ hepage} % Pagenumbering
enewcommand{headrulewidth}{0pt} % Remove header underlines
enewcommand{footrulewidth}{0pt} % Remove footer underlines
setlength{headheight}{13.6pt}
%%% Equation and float numbering
umberwithin{equation}{section} % Equationnumbering: section.eq#
umberwithin{figure}{section} % Figurenumbering: section.fig#
umberwithin{table}{section} % Tablenumbering: section.tab#
%%% Maketitle metadata
ewcommand{horrule}[1]{
ule{linewidth}{#1}} % Horizontal rule
itle{
%vspace{-1in}
usefont{OT1}{bch}{b}{n}
ormalfont
ormalsize extsc{University of Chinese Academy of Sciences, Math Department, Autumn 2017} \
%Grade (entered by Greg Lau): pts/40 pts} \ [25pt]
horrule{0.5pt} \[0.4cm]
huge Operating System Weekly Homework 03 \
%and 53;(Ch. 4)2,6,14,15 \
horrule{2pt} \[0.5cm]
}
author{
ormalfont
ormalsize
Xinze Li, Student ID 2015K8009906024\[-3pt]
ormalsize
%February 19, 2014
}
date{}
%%% Begin document
egin{document}
maketitle
%egin{section}
section{Problem 1}
subsection{description}
subsection{solution}
iffalse
egin{equation}
left{
egin{array}{l}
X 3 5 6 9 (Xleq 3)\
3 X 5 6 9 (3 < Xleq 5) \
3 5 X 6 9 (5< Xleq 6)\
3 5 6 X 9 (6<Xleq 9)\
3 5 6 9 X (9<X)
end{array}
ight.
end{equation}
fi%use iffalse to comment a section of codes
egin{spacing}{1.8}
egin{equation}
avg\_rsp\_time(X) = left{
egin{array}{l}
X + 4.6 (Xleq 3)\
dfrac{4X}{5} + 4.6 (3 < Xleq 5) \
dfrac{3X}{5} + 4.6 (5< Xleq 6)\
dfrac{2X}{5} + 4.6 (6<Xleq 9)\
dfrac{X}{5} + 4.6 (9<X)
end{array}
ight.
end{equation}
end{spacing}
section{Problem 2}
subsection{description}
subsection{solution}
section{Problem 3}
subsection{description}
subsection{solution}
%%% End document
end{document}
Use pdflatex to edit it.