3

How to write the section and examples in different colour, such as the title with blue colour

\documentclass[20pt,a4paper]{extarticle}
\usepackage[a4paper,margin=6mm]{geometry}
\usepackage{amsmath}
\usepackage{hyperref}

\title{\LaTeX\ Mathematics Examples}


\begin{document}

\maketitle

%\tableofcontents



\section{Delimiters}

See how the delimiters are of reasonable size in these examples
\begin{displaymath}
    \left(a+b\right)\left[1-\frac{b}{a+b}\right]=a\,,
\end{displaymath}
\begin{displaymath}
    \sqrt{|xy|}\leq\left|\frac{x+y}{2}\right|,
\end{displaymath}
even when there is no matching delimiter
\begin{displaymath}
    \int_a^bu\frac{d^2v}{dx^2}\,dx
    =\left.u\frac{dv}{dx}\right|_a^b
    -\int_a^b\frac{du}{dx}\frac{dv}{dx}\,dx.
\end{displaymath}






\section{Spacing}

Differentials often need a bit of help with their spacing as in
\begin{displaymath}
    \iint xy^2\,dx\,dy 
    =\frac{1}{6}x^2y^3,
\end{displaymath}
whereas vector problems often lead to statements such as
\begin{displaymath}
    u=\frac{-y}{x^2+y^2}\,,\quad
    v=\frac{x}{x^2+y^2}\,,\quad\text{and}\quad
    w=0\,.
\end{displaymath}









\section{Theorems et al.}

\newtheorem{theorem}{Theorem}
\newtheorem{corollary}[theorem]{Corollary}
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{definition}[theorem]{Definition}

\begin{definition}[right-angled triangles] \label{def:tri}
A \emph{right-angled triangle} is a triangle whose sides of length~\(a\), \(b\) and~\(c\), in some permutation of order, satisfies \(a^2+b^2=c^2\).
\end{definition}

\begin{lemma} 
The triangle with sides of length~\(3\), \(4\) and~\(5\) is right-angled.
\end{lemma}

This lemma follows from the Definition~\ref{def:tri} as \(3^2+4^2=9+16=25=5^2\).

\begin{theorem}[Pythagorean triplets] \label{thm:py}
Triangles with sides of length \(a=p^2-q^2\), \(b=2pq\) and \(c=p^2+q^2\) are right-angled triangles.
\end{theorem}

Prove this Theorem~\ref{thm:py} by the algebra \(a^2+b^2 =(p^2-q^2)^2+(2pq)^2
=p^4-2p^2q^2+q^4+4p^2q^2
=p^4+2p^2q^2+q^4
=(p^2+q^2)^2 =c^2\).


\end{document}
3

For section titles, you can use titlesec and do

\usepackage{titlesec}
\titleformat*{\section}{\color{magenta}}
\titleformat*{\subsection}{\color{Brown}}

To use Brown colour, you have to pass dvipsnames option to xcolor package.

For theorem titles etc you can do

\newtheorem{theorem}{\color{blue}Theorem}
\newtheorem{corollary}[theorem]{\color{blue}Corollary}
\newtheorem{lemma}[theorem]{\color{blue}Lemma}
\newtheorem{definition}[theorem]{\color{blue}Definition}

For theorems etc, there may be a better way, but I am unaware of them.

Code:

\documentclass[20pt,a4paper]{extarticle}
\usepackage[a4paper,margin=6mm]{geometry}
\usepackage{amsmath}
\usepackage[dvipsnames]{xcolor}    %% dvipsnames has Brown colour
\usepackage{hyperref}

\usepackage{titlesec}
\titleformat*{\section}{\color{magenta}}
\titleformat*{\subsection}{\color{Brown}}

\title{\LaTeX\ Mathematics Examples}


\begin{document}

\maketitle

%\tableofcontents



\section{Delimiters}
\subsection{Some subsection}

See how the delimiters are of reasonable size in these examples
\begin{displaymath}
    \left(a+b\right)\left[1-\frac{b}{a+b}\right]=a\,,
\end{displaymath}
\begin{displaymath}
    \sqrt{|xy|}\leq\left|\frac{x+y}{2}\right|,
\end{displaymath}
even when there is no matching delimiter
\begin{displaymath}
    \int_a^bu\frac{d^2v}{dx^2}\,dx
    =\left.u\frac{dv}{dx}\right|_a^b
    -\int_a^b\frac{du}{dx}\frac{dv}{dx}\,dx.
\end{displaymath}

\section{Spacing}

Differentials often need a bit of help with their spacing as in
\begin{displaymath}
    \iint xy^2\,dx\,dy
    =\frac{1}{6}x^2y^3,
\end{displaymath}
whereas vector problems often lead to statements such as
\begin{displaymath}
    u=\frac{-y}{x^2+y^2}\,,\quad
    v=\frac{x}{x^2+y^2}\,,\quad\text{and}\quad
    w=0\,.
\end{displaymath}

\section{Theorems et al.}

\newtheorem{theorem}{\color{blue}Theorem}
\newtheorem{corollary}[theorem]{\color{blue}Corollary}
\newtheorem{lemma}[theorem]{\color{blue}Lemma}
\newtheorem{definition}[theorem]{\color{blue}Definition}

\begin{definition}[right-angled triangles] \label{def:tri}
A \emph{right-angled triangle} is a triangle whose sides of length~\(a\), \(b\) and~\(c\), in some permutation of order, satisfies \(a^2+b^2=c^2\).
\end{definition}

\begin{lemma}
The triangle with sides of length~\(3\), \(4\) and~\(5\) is right-angled.
\end{lemma}

This lemma follows from the Definition~\ref{def:tri} as \(3^2+4^2=9+16=25=5^2\).

\begin{theorem}[Pythagorean triplets] \label{thm:py}
Triangles with sides of length \(a=p^2-q^2\), \(b=2pq\) and \(c=p^2+q^2\) are right-angled triangles.
\end{theorem}

Prove this Theorem~\ref{thm:py} by the algebra \(a^2+b^2 =(p^2-q^2)^2+(2pq)^2
=p^4-2p^2q^2+q^4+4p^2q^2
=p^4+2p^2q^2+q^4
=(p^2+q^2)^2 =c^2\).


\end{document}

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  • I tried to use Brown colour but does not work I use this package but still does not work \usepackage[Brown,dvipsnames]{color} \definecolor{light-Brown}{Brown}{0.95} – percusse Sep 18 '14 at 6:19
  • How about subsection, how can I make it different colour. Thanks – percusse Sep 18 '14 at 6:36
  • @percusse Please see the updated answer. – user11232 Sep 18 '14 at 6:49
  • Thank you Harish, I really appreciate your help. Thanks a lot – percusse Sep 18 '14 at 6:53
  • @percusse Thanks are conveyed through upvoting (all!) and accepting the most useful answer (after a reasonable delay to see if other (better) answers pop up) in this site. For details, please see How do you accept an answer – user11232 Sep 18 '14 at 6:55

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