[Tex/LaTex] Write case condition on two lines

equations

I have this equation:

which must be inserted in a Office document. But it is too large, so I want to add a line return in the middle of the 2nd and 3rd condition such that the new line starts exactly at the same point as before (not in the left area of the "equation system").

s(g) =
\begin{cases}
  q_i / n
  & se \; \exists i:1 \leq i \leq k \enspace t.c. \enspace g \in [x_{i-1}, x_i] \\
  q_1 / n - P \left(q_1/n, x_0 - g \right)
  & se \; g \notin [x_{i-1}, x_i] \: \forall i: 1 \leq i \leq k \;\; e \; 
  \left( x_0 - g \right) \leq \left( g - x_k \right) \\
  \left q_k / n  - P \left(q_k/n, g - x_k \right)
  & se \; g \notin [x_{i-1}, x_i] \: \forall i: 1 \leq i \leq k \;\; e \; 
  \left( x_0 - g \right) > \left( g - x_k \right)
\end{cases}

Best Answer

Are you looking for something like this? I am not sure if "e" and "se" are words or math... if words, then \textrm{e} and \textrm{se} would make proper sense.

REVISED SOLUTION (if only left alignment is required)

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[
s(g) =
\begin{cases}
  q_i / n
  & se \; \exists i:1 \leq i \leq k \enspace t.c. \enspace g \in [x_{i-1}, x_i] \\
  q_1 / n - P \left(q_1/n, x_0 - g \right)
  & se \; g \notin [x_{i-1}, x_i] \: \forall i: 1 \leq i \leq k \;\;\\
  & e \; \left( x_0 - g \right) \leq \left( g - x_k \right) \\
  q_k / n  - P \left(q_k/n, g - x_k \right)
  & se \; g \notin [x_{i-1}, x_i] \: \forall i: 1 \leq i \leq k \;\; \\
  & e \; \left( x_0 - g \right) > \left( g - x_k \right)
\end{cases}
\]
\end{document}

ORIGINAL SOLUTION

\documentclass{article}
\usepackage{amsmath,stackengine}
\stackMath
\begin{document}
\[
\def\stackalignment{l}
s(g) =
\begin{cases}
  q_i / n
  & se \; \exists i:1 \leq i \leq k \enspace t.c. \enspace g \in [x_{i-1}, x_i] \\
  q_1 / n - P \left(q_1/n, x_0 - g \right)
  & \stackunder{
    se \; g \notin [x_{i-1}, x_i] \: \forall i: 1 \leq i \leq k \;\;
  }{
   e \; \left( x_0 - g \right) \leq \left( g - x_k \right)
  } \\
  q_k / n  - P \left(q_k/n, g - x_k \right)
  & \stackunder{
    se \; g \notin [x_{i-1}, x_i] \: \forall i: 1 \leq i \leq k \;\; 
  }{
  e \; \left( x_0 - g \right) > \left( g - x_k \right)
  }
\end{cases}
\]
\end{document}

Related Solutions

[Tex/LaTex] Making a new environment combining equation and split

I wouldn't have expected this, but there's an easy answer; thanks to Stefan Kottwitz! (And thanks to Will Robertson for writing the package environ that I had never heard of before. He should have given this answer; with his package it works like a charm.)

\documentclass{article}
\usepackage{amsmath,environ}
\NewEnviron{example}{%
\begin{equation}\begin{split}
  \BODY
\end{split}\end{equation}
}
\begin{document}
\begin{example}
a &= b + c \\
  &= d + e
\end{example}
\end{document}

Some explanations can be found in Stefan's post behind the above link.

[Tex/LaTex] How to write the equations with conditions in two lines

You really want to use alignat or alignedat (the difference being that the former types two equations, the latter one equation on two lines)

\documentclass{amsart}
\begin{document}
  \begin{alignat}{8}
    \nu &= V_w &&= cz/l, & \qquad u&= U_0, &\qquad \text{at\quad} r &=R, \\
    \nu &\rightarrow V_e &&= az/l, &\qquad T &\rightarrow T_{\infty},&\qquad \text{as\quad} r &\rightarrow \infty,
  \end{alignat}

  \begin{equation}
    \begin{alignedat}{8}
      \nu &= V_w &&= cz/l, & \qquad u&= U_0, &\qquad \text{at\quad} r &=R, \\
      \nu &\rightarrow V_e &&= az/l, &\qquad T &\rightarrow T_{\infty},&\qquad \text{as\quad} r &\rightarrow \infty,
    \end{alignedat}
  \end{equation}

  \begin{equation*}
    \begin{alignedat}{8}
      \nu &= V_w &&= cz/l, & \qquad u&= U_0, &\qquad \text{at\quad} r &=R, \\
      \nu &\rightarrow V_e &&= az/l, &\qquad T &\rightarrow T_{\infty},&\qquad \text{as\quad} r &\rightarrow \infty,
    \end{alignedat}
  \end{equation*}

\end{document}

both environments are found in amsmath , which is loaded by amsart in my mwe

Best Answer

Related Solutions

[Tex/LaTex] Making a new environment combining equation and split

[Tex/LaTex] How to write the equations with conditions in two lines

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