I have the following set of subequations (amsmath):
\begin{subequations}
\begin{alignat}{3}
&\frac{\partial^2 \, (r \, \Pi_{1 \perp}^e)}{\partial r^2}+k^2 \, r \, \Pi_{1 \perp}^e &= E \, \varepsilon \, \sin{\vartheta} \, \sin{\varphi} \cdot e^{i \, k \, R + i \, \omega t}\\
\shortintertext{}
&\frac{1}{r} \, \frac{\partial^2 (r \, \Pi_{1 \perp}^e)}{\partial r \partial \vartheta}-i \, k \, \sqrt{\frac{\varepsilon}{\mu}} \, \frac{1}{\sin{\vartheta}} \, \frac{\partial \Pi_{2 \perp}^e}{\partial \varphi} &= E \, \varepsilon \, \cos{\theta} \, \sin{\varphi} \cdot e^{i \, k \, R + i \, \omega \, t}\\
\shortintertext{}
&\frac{1}{r \, \sin{\vartheta}} \, \frac{\partial^2 (r \, \Pi_{1 \perp}^e)}{\partial r \partial \varphi}+i \, k \, \sqrt{\frac{\varepsilon}{\mu}} \, \frac{\partial \Pi_{2 \perp}^e}{\partial \vartheta} &= E \, \cos{\varphi} \cdot e^{i \, k \, R+i \, \omega \, t}
\end{alignat}
\end{subequations}
(Try to ignore the math) I'm trying to align them at the beginning and at the equal sign, so it looks like this:
(Original German document I'm translating, By J. Meixner). Here's what mine looks like:
As you can see, it aligns correctly at the beginning but not at the equal signs. How can I make it line up?
\theta
,\epsilon
and\phi
, and redefine them in the preamble, I see no reason to use\var···
when the two variants are not present in the document.