# Alignment of different align environment

I have an issue when I try to align different "align" environments. This is my Latex code :

\documentclass[10pt, a4paper]{article}

\usepackage[english]{babel}
\usepackage[english]{isodate}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}

\usepackage{mathtools}
\usepackage{amsmath}
\usepackage{amssymb}

\begin{document}
\section{Example}
\subsection*{Degree 1}
\begin{align*}
C_1' & = C_1 \\
C_0' & = a_k + C_0
\end{align*}

\subsection*{Degree 2}
\begin{align*}
C_2' & = C_2 \\
C_1' & = 2 C_2 a_k + C_1 \\
C_0' & = C_2   a_k^2 + C_1   a_k + C_0
\end{align*}

\subsection*{Degree 3}
\begin{align*}
C_3' & = C_3 \\
C_2' & = 3 C_3 a_k + C_2 \\
C_1' & = 3 C_3 a_k^2 + 2 C_2 a_k + C_1 \\
C_0' & = C_3 a_k^3 + C_2   a_k^2 + C_1   a_k + C_0
\end{align*}

\subsection*{Degree 4}
\begin{align*}
C_4' & = C_4 \\
C_3' & = 4 C_4 a_k + C_3 \\
C_2' & = 6 C_4 a_k^2 + 3 C_3 a_k + C_2 \\
C_1' & = 4 C_4 a_k^3 + 3 C_3 a_k^2 + 2 C_2 a_k + C_1 \\
C_0' & = C_4 a_k^4 + C_3 a_k^3 + C_2 a_k^2 + C_1 a_k + C_0
\end{align*}

\subsection*{Degree 5}
\begin{align*}
C_5' & = C_5 \\
C_4' & = 5 C_5 a_k + C_4 \\
C_3' & = 10 C_5 a_k^2 + 4 C_4 a_k + C_3 \\
C_2' & = 10 C_5 a_k^3 + 6 C_4 a_k^2 + 3 C_3 a_k + C_2 \\
C_1' & = 5 C_5 a_k^4 + 4 C_4 a_k^3 + 3 C_3 a_k^2 + 2 C_2 a_k + C_1 \\
C_0' & = C_5 a_k^5 + C_4 a_k^4 + C_3 a_k^3 + C_2 a_k^2 + C_1 a_k + C_0
\end{align*}
\end{document}


And this is the output :

As you can see, equations are not well aligned. I want to align their left side on the same line but by keeping them in the middle of the page (is this clear ?)

With \intertext:

\documentclass[10pt, a4paper]{article}

\usepackage[english]{babel}
\usepackage[english]{isodate}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}

\usepackage{mathtools}
\usepackage{amsmath}
\usepackage{amssymb}

\begin{document}
\section{Example}
\subsection*{Degree 1}
\begin{align*}
C_1' & = C_1 \\
C_0' & = a_k + C_0
%
\intertext{\subsection*{Degree 2}}
C_2' & = C_2 \\
C_1' & = 2 C_2 a_k + C_1 \\
C_0' & = C_2   a_k^2 + C_1   a_k + C_0
%
\intertext{\subsection*{Degree 3}}
C_3' & = C_3 \\
C_2' & = 3 C_3 a_k + C_2 \\
C_1' & = 3 C_3 a_k^2 + 2 C_2 a_k + C_1 \\
C_0' & = C_3 a_k^3 + C_2   a_k^2 + C_1   a_k + C_0
%
\intertext{\subsection*{Degree 4}}
C_4' & = C_4 \\
C_3' & = 4 C_4 a_k + C_3 \\
C_2' & = 6 C_4 a_k^2 + 3 C_3 a_k + C_2 \\
C_1' & = 4 C_4 a_k^3 + 3 C_3 a_k^2 + 2 C_2 a_k + C_1 \\
C_0' & = C_4 a_k^4 + C_3 a_k^3 + C_2 a_k^2 + C_1 a_k + C_0
%
\intertext{\subsection*{Degree 5}}
C_5' & = C_5 \\
C_4' & = 5 C_5 a_k + C_4 \\
C_3' & = 10 C_5 a_k^2 + 4 C_4 a_k + C_3 \\
C_2' & = 10 C_5 a_k^3 + 6 C_4 a_k^2 + 3 C_3 a_k + C_2 \\
C_1' & = 5 C_5 a_k^4 + 4 C_4 a_k^3 + 3 C_3 a_k^2 + 2 C_2 a_k + C_1 \\
C_0' & = C_5 a_k^5 + C_4 a_k^4 + C_3 a_k^3 + C_2 a_k^2 + C_1 a_k + C_0
\end{align*}
\end{document}

• Precisely what I was looking for, thanks – graille Aug 17 at 13:00
• @graille: You're welcome. If you want to, you could also define your own command ro avoid cepeatedly typing Degree and to avoid manual numbering. – leandriis Aug 17 at 13:07