I want to have several equations be aligned using alignat.
When I use alignat the result is fine (see code section 1), irrespective of the length of the equation. However, when I use alignat in a subequations environment the result isn’t correct and it seems to depend on the length of the equation (see code section 2).
How can this problem be solved? Thanks for your support in advance.
Section 1: code without using subequations:
\begin{alignat}{2}
&a &&=b ~,\label{1a}\\[1ex]
&alpha &&=beta~,\label{1b} \\[1ex]
&c &&=\frac{\num{72000}\cdot\num{50000}\,(1 - \num{0.30})}{\num{50000}\,(1 - \num{0.30}) -
2\cdot\num{72000}\cdot\num{0.25}^2} = \SI{96923}{kN/m^2} \label{1c} \\[1ex]
&cc &&=\frac{\num{72000}\cdot\num{50000}\,(1 - \num{0.30})}{\num{50000}\,(1 - \num{0.30}) -
2\cdot\num{72000}\cdot\num{0.25}^2} = \SI{96923.08}{kN/m^2} \label{1d}
\end{alignat}%
Section 2: code with subequations:
{\allowdisplaybreaks [4]
\begin{subequations}\label{1}
%\noeqref{1a,1b,1c,1d}
\begin{alignat}{2}
&a &&=b ~,\label{1a}\\[1ex]
&alpha &&=beta~,\label{1b} \\[1ex]
&c &&=\frac{\num{72000}\cdot\num{50000}\,(1 - \num{0.30})}{\num{50000}\,(1 - \num{0.30}) -
2\cdot\num{72000}\cdot\num{0.25}^2} = \SI{96923}{kN/m^2} \label{1c} \\[1ex]
&cc &&=\frac{\num{72000}\cdot\num{50000}\,(1 - \num{0.30})}{\num{50000}\,(1 - \num{0.30}) -
2\cdot\num{72000}\cdot\num{0.25}^2} = \SI{96923.08}{kN/m^2} \label{1d}
\end{alignat}
\end{subequations}}%
