Math & Science ⇒ Only one equation number in {align*}

[zimbodel]

This one keeps biting me for years, and I cannot find a solution doing online search.

How do I get only one equation number displayed in an align* environment

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\begin{align*}
\end{align*}

containing several equations?

[Stefan Kottwitz]

Hi zimbodel,

I would use an equation environment and within this an aligned environment.

Stefan

[zimbodel]

Silly me now I remember....
It always catches me after I dont use latex for a while and I always seem to forget that.
It is one of those tricks that only makes sense once you know about it.
Thanks.

[marbocam]

I'm having the same issue, but latex doesn't like the nesting..

Package amsmath Error: Erroneous nesting of equation structures;
(amsmath) trying to recover with `aligned'.

What am I doing wrong?

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\begin{equation}
\begin{align}
	{E}_{PD}\ \left(t \right) =& \!\left[ {T}_o{J}_o\left({{m}_{RF}} \right) + j{J}_1\left({{m}_{RF}} \right){e}^{j\frac{1}{2}{\beta }_2L\omega _{RF}^2} \right.\\ & \times \left({{e}^{j{\omega }_{RF}t} + {e}^{ - j{\omega }_{RF}t}} \right) \\ & \!-\! \left. {J}_2\left({{m}_{RF}} \right){e}^{j2{\beta }_2L\omega _{RF}^2}\!\left({{e}^{j2{\omega }_{RF}t} \!+\! {e}^{ - j2{\omega }_{RF}t}} \!\right) \!\right] e ^{j{\omega }_ot}\\ & + {T}_o{J}_o\left({{m}_{RF}} \right){e}^{j\frac{1}{2}{\beta }_2L\omega _{IF}^2}\left({m}_ + \cdot {e}^{j{\omega }_{IF}t} + {m}_ - \right.\\ & \cdot \left. {e}^{ - j{\omega }_{IF}t} \right){e}^{j{\omega }_ot} + j{J}_1\left({{m}_{RF}} \right){e}^{j\frac{1}{2}{\beta }_2L{{\left({{\omega }_{RF} + {\omega }_{IF}} \right)}}^2}\\ & \times \left({{m}_ + {e}^{j\left({{\omega }_{RF} + {\omega }_{IF}} \right)t} + {m}_ - {e}^{ - j\left({{\omega }_{RF} + {\omega }_{IF}} \right)t}} \right){e}^{j{\omega }_ot} \\ & + j{J}_1\left({{m}_{RF}} \right){e}^{j\frac{1}{2}{\beta }_2L{{\left({{\omega }_{RF} - {\omega }_{IF}} \right)}}^2}\\ &\!\times\! \left({{m}_ - \cdot {e}^{j\left({{\omega }_{RF} \!-\! {\omega }_{IF}} \right)t} \!+\! {m}_ + \cdot {e}^{ - j\left({{\omega }_{RF} \!-\! {\omega }_{IF}} \right)t}} \right){e}^{j{\omega }_ot} \\ & - {J}_2\left({{m}_{RF}} \right){e}^{j\frac{1}{2}{\beta }_2L{{\left({2{\omega }_{RF} + {\omega }_{IF}} \right)}}^2}\\ & \times \left({{m}_ + \cdot {e}^{j\left({2{\omega }_{RF} + {\omega }_{IF}} \right)t} + {m}_ - \cdot {e}^{ - j\left({2{\omega }_{RF} + {\omega }_{IF}} \right)t}} \right)\\ & \times {e}^{j{\omega }_ot} - {J}_2\left({{m}_{RF}} \right){e}^{j\frac{1}{2}{\beta }_2L{{\left({2{\omega }_{RF} - {\omega }_{IF}} \right)}}^2}\\ & \!\times\! \left({{m}_ - \cdot {e}^{j\!\left({2{\omega }_{RF} \!-\! {\omega }_{IF}} \!\right)t} \!+\! {m}_ + \cdot {e}^{ - j\!\left({2{\omega }_{RF} \!-\! {\omega }_{IF}} \!\right)t}} \!\right){e}^{j{\omega }_ot}
\end{align}
\end{equation}\label{poc_E_PD_t}

[marbocam]

Anyway, I fixed it with \nonumber... Still, I would like to know how to nest the aligned..

[Stefan Kottwitz]

@marbocam Use aligned instead of align, then it works.

Stefan

[marbocam]

I did work, but not within a table... What am I doing worng this time¿? This should work, right?

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\begin{table}[h]
\caption{Analytical Terms of the Photocurrent Amplitude at mmW Band}
\centering
\begin{tabular}{p{1cm}p{1cm}p{9cm}}
\hline\hline
\centering L&$\centering T_0$& \centering\arraybackslash $i_{RF}(2\omega_{RF}-\omega_{IF})$\\
\hline
\[\text{0}\] & \[\text{1}\] & \begin{equation} 0 \label{poc_eq_10} \end{equation}\\
\[\text{L}\] & \[\text{1}\] & \begin{equation}\begin{aligned}
&2 \Re P_0 m_{AM}\left(\frac{m_{RF}}{2}\right)^2 sin^2 \Theta
& \cdot \left[\sqrt{1+\alpha^2}cos(\Theta - atan \alpha) + j\alpha \frac{\kappa P_0}{\omega_{IF}}sin\Theta \right] \label{poc_eq_11}
\end{aligned}\end{equation}\\
\[\text{L}\] & \[\text{0}\] &\begin{equation}\begin{aligned}
&\Re P_0 m_{AM}\left(\frac{m_{RF}}{2}\right)^2
& \cdot \left[\sqrt{1+\alpha^2}cos(\Theta - atan \alpha) + j\alpha \frac{\kappa P_0}{\omega_{IF}}sin\Theta \right] \label{poc_eq_12}
\end{aligned}\end{equation}\\
\hline\hline
\end{tabular}\label{poc_Table_1}

[Stefan Kottwitz]

This should work. However, you don't have \end{table}, so it brings an error. You need to load the array package; perhaps you do it, but I don't see your document preamble. It would always be good to post a small complete example, otherwise, each reader needs to add code (which may be different to your other code) to compile it or cannot test the code.

Stefan

[marbocam]

Sorry for that.. My original code does contain \end{table}...

I finally figured what was wrong with my code, I needed to add \\ after the first line of the equation

[Stefan Kottwitz]

table-equation.png (34.1 KiB) Viewed 13069 times

Ah, perhaps you mean the \\ within the "aligned" part, since \\ sepearate the rows in a multi-line equation, but the equation environment itself is single-line without \\ Just to be clear to where the \\ belongs.

Stefan