[Tex/LaTex] Raise equation number position from new line

amsmathequationsnumberingvertical alignment

I am trying to write an equation in a multicolumn environment and while there is space on the final line for the equation number, LaTeX is seemingly putting it on a new line.

\documentclass[a4paper, 12pt]{article}
\usepackage{lipsum, amsmath, multicol, geometry}
\geometry{left=20mm, right=20mm, top=20mm, bottom=20mm}
\begin{document}
\begin{multicols}{2}
Using central differences for the first and second order derivative our numerical scheme becomes
\begin{equation}
\begin{aligned}
h_j^{n+1} =  h_j^n &+  \dfrac{\Delta t \left(h_j^n\right)^3}{(\Delta x)^2} 
\left(h_{j+1}^n - 2 h_j^n + h_{j-1}^n\right)\\ 
&+  \dfrac{3\Delta t \left(h_j^n\right)^2}{4(\Delta x)^2} 
\left(h_{j+1}^n - h_{j-1}^n\right)
\end{aligned}
\label{eqt:numerical_scheme}
\end{equation}
where we notice something\\
\lipsum[2]
\end{multicols}
\end{document}

gives the following:

misplaced equation number

I would like the equation number to be higher on the final line where there is room. I have tried swapping the lines and various environments, but no luck.

Any help would be appreciated.

Best Answer

enter image description here

\documentclass{article}
\usepackage{multicol,amsmath}
\addtolength\textwidth{2cm}
\begin{document}

\begin{multicols}{2}
Using central differences for the first and second order derivative our numerical scheme becomes
\begin{gather}
\begin{aligned}
h_j^{n+1} =  h_j^n &+  \dfrac{\Delta t \left(h_j^n\right)^3}{(\Delta x)^2} 
\left(h_{j+1}^n - 2 h_j^n + h_{j-1}^n\right)\\ 
&+  \dfrac{3\Delta t \left(h_j^n\right)^2}{4(\Delta x)^2} 
\left(h_{j+1}^n - h_{j-1}^n\right)
\end{aligned}
\label{eqt:numerical_scheme1}
\raisetag{20pt}
\end{gather}
where we notice something

Using central differences for the first and second order derivative our numerical scheme becomes
\begin{align}
h_j^{n+1} =  h_j^n &+  \dfrac{\Delta t \left(h_j^n\right)^3}{(\Delta x)^2} 
\left(h_{j+1}^n - 2 h_j^n + h_{j-1}^n\right)\nonumber\\ 
&+  \dfrac{3\Delta t \left(h_j^n\right)^2}{4(\Delta x)^2} 
\left(h_{j+1}^n - h_{j-1}^n\right)
\label{eqt:numerical_scheme2}
\end{align}
where we notice something

\end{multicols}

\end{document}

Please always post full documents, I had to guess a text width to get the effect that you showed. You can use \raisetag (But apparently not in equation so I used a one line gather) or you can use align and just number one line.

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