[Tex/LaTex] how can I write equation numbers in latex

equationsnumbering

how can I write equation numbers in latex. like 1, 2, and so on.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[
\pdv{T^k}{t} = 
-\frac{\dot{f}_t^k}{A\varepsilon_{\textrm{cat}}C_t^k}
 \frac{T_i^k-T_i^{k-1}}{\Delta z}
+\frac{\pi D_i}{A\varepsilon_{\textrm{cat}}C_t^kC_p^k}
+\frac{\rho_{\textrm{cat}}a}{\varepsilon_{\textrm{cat}}C_t^kC_p^k}
\sum_{i=1}^{N} \eta_i^kr_i^k(-\Delta H_{\!f,i}^k)
\]
\end{document}

Best Answer

In addition to the excellent suggestions above in comments section -- if you wish to do manual numbering add the \tag syntax at the end of the equation --\tag{..3.1.1a,b} \label{myeq} --the \label syntax for referencing can be plugged in if desired

Off course you can revert to auto numbering with the equation environment

And the negative points are not mine(-1)

enter image description here

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[
{T^k}{t} = 
-\frac{\dot{f}_t^k}{A\varepsilon_{\textrm{cat}}C_t^k}
 \frac{T_i^k-T_i^{k-1}}{\Delta z}
+\frac{\pi D_i}{A\varepsilon_{\textrm{cat}}C_t^kC_p^k}
+\frac{\rho_{\textrm{cat}}a}{\varepsilon_{\textrm{cat}}C_t^kC_p^k}
\sum_{i=1}^{N} \eta_i^kr_i^k(-\Delta H_{\!f,i}^k) \tag{..3.1.1a,b} \label{myeq}
\]

For example, see \eqref{myeq}.
\end{document}
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