# Aligning equations - System of equations all numbered

I tried to write a system of equations with all equations numerated, but they are not aligned:

\begin{empheq}[left=\empheqlbrace]{align}
R_a = R_d\\
\frac{dq(t)}{dt} = ir - r_d(t) \\
q(0)=0 \\
r_d(t) = TTR(t) R_d
\end{empheq}


How can I solve this problem?

Thank you very much in advance.

• alignment points in align are marked by & usually just before an = – David Carlisle Dec 2 '17 at 23:04
• Hello @DavidCarlisle can you show me how please? I tried also with &, my result is bad. – Gennaro Arguzzi Dec 2 '17 at 23:06
• make a proper test file that shows the problem and can be run, and someone will no doubt show how to fix it – David Carlisle Dec 2 '17 at 23:07
• Thank you @DavidCarlisle I solved placing & before each equation. – Gennaro Arguzzi Dec 2 '17 at 23:10
• Aligning on = is more conventional (if you put & before each equation you are marking up each row as just having a right hand side but no left hand term in the equation – David Carlisle Dec 2 '17 at 23:13

Mark alignment points with & :

\documentclass{article}

\usepackage{empheq}
\usepackage{amsmath}

\begin{document}

\begin{empheq}[left=\empheqlbrace]{align}
R_a &= R_d\\
\frac{dq(t)}{dt} &= ir - r_d(t) \\
q(0)&=0 \\
r_d(t) &= TTR(t) R_d
\end{empheq}
\end{document}