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...
Help me please.
\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
\begin{equation}
at \,\,\, r^{*}=1: \,\,\,\,\, T_{1}^{*}=0
\end{equation}
\[
at \,\,\, r^{*}=\phi:\,\,\,\,\, \begin{cases}
T_{1}^{*}= T_{2}^{*} \\
\\
\frac{\partial T_{1}^{*}}{\partial r^{*}}=\frac {\partial T_{2}^{*}}{\partial r^{*}}
\end{cases}
\]
\\
\[
\begin{vmatrix}
F_{1}(1) & F_{2}(1) & 0\\
F_{1}(\phi) & F_{2}(\phi) & -F_{3}(\phi) \\
F^{'}_{1}(\phi) & F^{'}_{2}(\phi) & -F^{'}_{3}(\phi)
\end{vmatrix}=0
\]
\end{document}
\[...\]which does not number by default, use\begin{equation}.\end{equation}/\begin{align}.\end{align}instead. – moewe Mar 30 '15 at 09:06