# Numbering this special equation [closed]

I have some problems. I attache the Tex file for you. I didn't put nember in first page, but the second page started from 2 and the passages are untidy in pdf (not left to right as the same way I wrote in Latex file).

In the second page I want to nymber the second equation by 2.1 and 2.2, but I cannot number it. Also the third equation should has label 3...

‎\begin{document}‎
\begin{center}‎
‎\includegraphics[scale=0.8]{1.jpg}‎
‎\end{center}‎
‎\begin{center}‎
\textbf{Department of Mechanical Engineering}\\
‎\vspace{1.5cm}‎
\textbf{Fluid Mechanics}\\
‎\vspace{1.5cm}‎
\textit{Report Title: ‎}\\‎
\textbf{Laminar Flow ‎}\\‎
‎\vspace{1.5cm}‎
‎%\includegraphics[scale=0.3]{zia.jpg}\\‎
Student: \textbf{Zia Daghighi}\\
‎\vspace{1cm}‎
Teacher: \textbf{Nouroz}
‎\end{center}‎‎‎
‎\thispagestyle{empty}‎
‎\newpage‎‎‎
$$at \,\,\‎, ‎r^{*}=1‎: ‎\,\,\,\,\‎, ‎T_{1}^{*}=0$$
‎$‎ ‎at \,\,\‎, ‎r^{*}=\phi:\,\,\,\,\‎, ‎\begin{cases}‎ ‎T_{1}^{*}= T_{2}^{*} \\‎ ‎\\‎ ‎\frac{\partial T_{1}^{*}}{\partial r^{*}}=\frac {\partial T_{2}^{*}}{\partial r^{*}}‎ ‎\end{cases}‎ ‎$‎
‎\\‎
‎$‎ ‎\begin{vmatrix}‎ ‎F_{1}(1) & F_{2}(1) & 0\\‎ ‎F_{1}(\phi) & F_{2}(\phi) &‎ -‎F_{3}(\phi) \\‎ ‎F^{'}_{1}(\phi) & F^{'}_{2}(\phi) &‎ -‎F^{'}_{3}(\phi)‎ ‎\end{vmatrix}=0‎ ‎$‎

‎\end{document}‎

• Welcome to TeX.SX! You can have a look at our starter guide to familiarize yourself further with our format. In the nature of this Q&A site lies that we normally only ask one question per ... eh .. question. For your first question see How to set page counter by skipping first page? and No page numbering. For your unnumbered equations you use $...$ which does not number by default, use $$.$$/\begin{align}.\end{align} instead. Mar 30 '15 at 9:06

Do you mean like this?

% arara: pdflatex

\documentclass[fleqn]{article}
\usepackage{mathtools}
\usepackage[subnum]{cases}

\begin{document}‎
$$\text{at } r^{*}=1‎: \quad ‎T_{1}^{*}=0$$
$$\begin{vmatrix}‎ ‎F_{1}(1) & F_{2}(1) & 0 \\‎ ‎F_{1}(\phi) & F_{2}(\phi) &‎ -‎F_{3}(\phi) \\‎ ‎F'_{1}(\phi) & F'_{2}(\phi) &‎ -‎F'_{3}(\phi) ‎ \end{vmatrix}=0‎$$