# Formulas should start at the same position

I am a very beginner of LaTeX and I do not have any kind of experience with it.

How can I make formulas start at the same position such that they are aligned exactly underneath each other.

\documentclass[oneside,12pt]{scrartcl}
\usepackage[ngerman]{babel}
\usepackage[fixamsmath,disallowspaces]{mathtools}
\begin{document}

\underline{Verschiebare Ger{\"a}te}

\begin{equation*}
P_j(t,s_j) =
\begin{cases}
0 & \text{f"ur } t < s_j \ Q_j(t-s_j) & \text{f"ur } s_j \leq t \leq s_j + p_j \ 0 & \text{f"ur } t \textgreater s_j + p_j
\end{cases}
mit s_j = r_j + \Delta t \ \Delta t \leq tDoF
\end{equation*}
\end{document}


My problem refers to the last two formulars. I want the \Delta t to start exactly underneath the s_j, so the equality signs of those two formulars should start at the same position, but underneath each other.

• Perhaps the documentclass option fleqn is what you are searching for? – Juri Robl Feb 8 '15 at 12:40
• Hi and welcome, instead of shooting into the blue, a bit of scientific preparation might be a good idea. If you want to know more about typesetting maths, please have a look at Mathmode. – Johannes_B Feb 8 '15 at 12:43
• Welcome to TeX.SX! You can have a look at our starter guide to familiarize yourself further with our format. A suggestion: Do us a favour and change your username to something more telling than "user1234". – Martin Schröder Feb 8 '15 at 15:40
• You might be interested in TeXwelt.de, agerman site with the same Question and Anwer format and goLaTeX, a classical german discussion forum. – Johannes_B Feb 8 '15 at 15:51
• Remember to accept one of the answers if you find it useful. – Svend Tveskæg Feb 8 '15 at 17:22

I'm not sure I've guessed what you want but here is a try:

\documentclass{scrartcl}

\usepackage[showframe]{geometry} % used to show page width
\usepackage{mathtools}

\begin{document}

\begin{equation*}
P_{j}(t, s_{j}) =
\begin{cases}
0                & \text{f{\"u}r $t < s_{j}$,}\\
Q_{j}(t - s_{j}) & \text{f{\"u}r $s_{j} \leq t \leq s_{j} + p_{j}$,}\\
0                & \text{f{\"u}r $t > s_{j} + p_{j}$,}
\end{cases}
\end{equation*}
mit $s_{j} = r_{j} + \Delta t$ f{\"u}r $\Delta t \leq tDoF$.

\end{document}


You can use the align environment to align math at specific parts:

\documentclass[oneside,12pt]{scrartcl}
\usepackage[ngerman]{babel}
\usepackage[fixamsmath,disallowspaces]{mathtools}
\begin{document}

\begin{align*}
P_j(t,s_j) &= \begin{cases}
0 &  \text{f"ur  } t < s_j   \\
Q_j(t-s_j) & \text{f"ur  } s_j  \leq t \leq  s_j  + p_j  \\
0 & \text{f"ur  } t \textgreater s_j + p_j
\end{cases}\\
%\intertext{mit}\\
\text{mit }&s_j = r_j +  \Delta t  \\
&\Delta t \leq tDoF
\end{align*}
\end{document}


To add text on it's own line you can use intertext or if you want it inline use text as you already did.

Or if you want the equation symbols directly underneath each other:

\text{mit }s_j &= r_j +  \Delta t  \\
\Delta t &\leq tDoF


You can use the alignenvironment. Be careful to use \\ to break lines.

\documentclass[oneside,12pt]{scrartcl}
\usepackage[ngerman]{babel}
\usepackage{amsmath}
\usepackage[fixamsmath,disallowspaces]{mathtools}

\begin{document}

\underline{Verschiebare Ger{\"a}te}
\begin{align*}
P_j(t,s_j) &= \begin{cases} 0 & \text{f"ur } t < s_j \\
Q_j(t-s_j) & \text{f"ur } s_j \leq t \leq s_j + p_j \\
0 & \text{f"ur } t \textgreater s_j + p_j \end{cases} \\
\text{mit } s_j& = r_j + \Delta t \ \Delta t \leq tDoF
\end{align*}

\end{document}