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I have to align multiple equations with cases. I can align the left bracket, but i can't align the cases on the right between different the different equations. I maneged to align only the cases of a single equation. I tried using the aligned and array environments like:

\begin{equation}
\begin{aligned}
\alpha^{S / C} & =\left\{\begin{array}{lr}
0 & \lambda_c \leq-1.95 \\
0.3+0.4\left(\lambda_c+1.2\right) & -1.95<\lambda_c<0.55 \\
1 & \lambda_c \geq 0.55
\end{array}\right. \\ 
\mu_1^{S / C} & =\left\{\begin{array}{lr}
-0.6 & \lambda_c \leq-1.1 \\
-0.6-0.318\left(\lambda_c+1.1\right) & -1.1<\lambda_c<0 \\
-0.95 & \lambda_c \geq 0
\end{array}\right. \\
\sigma_1^{S / C} & =\left\{\begin{array}{lr}
0.1 & \lambda_c \leq-1.3 \\
0.1+0.2\left(\lambda_c+1.3\right) & -1.3<\lambda_c<-0.3 \\
0.3 & \lambda_c \geq-0.3
\end{array}\right. \\
\mu_2^{S / C} & =\left\{\begin{array}{lr}
-1.2 & \lambda_c \leq-0.7 \\
-1.2-1.333\left(\lambda_c+0.7\right) & -0.7<\lambda_c<-0.1 \\
-2.0 & \lambda_c \geq-0.1 \\
\end{array}\right. \\
\sigma_2^{S / C} & =\left\{\begin{array}{lr}
0.5 &\lambda_c \leq-0.5  \\
0.5-\left(\lambda_c+0.5\right) &  -0.5<\lambda_c<-0.3\\
0.3 & \lambda_c \geq-0.3
\end{array}\right.
\end{aligned}
\end{equation}

or using the aligned and cases environments like:

\begin{equation}
    \begin{aligned}
        \alpha^{S / C} & = \begin{cases}
            0 & \lambda_c \leq-1.95 \\
            0.3+0.4\left(\lambda_c+1.2\right) & -1.95<\lambda_c<0.55 \\
            1 & \lambda_c \geq 0.55 \\
        \end{cases}\\
        \mu_1^{S / C} & =\begin{cases}
            -0.6 & \lambda_c \leq-1.1 \\
            -0.6-0.318\left(\lambda_c+1.1\right) & -1.1<\lambda_c<0 \\
            -0.95 & \lambda_c \geq 0
        \end{cases}\\
        \sigma_1^{S / C} & =\begin{cases}
            0.1 & \lambda_c \leq-1.3 \\
            0.1+0.2\left(\lambda_c+1.3\right) & -1.3<\lambda_c<-0.3 \\
            0.3 & \lambda_c \geq-0.3
        \end{cases}\\
        \mu_2^{S / C} & =\begin{cases}
            -1.2 & \lambda_c \leq-0.7 \\
            -1.2-1.333\left(\lambda_c+0.7\right) & -0.7<\lambda_c<-0.1 \\
            -2.0 & \lambda_c \geq-0.1 \\
        \end{cases}\\
        \sigma_2^{S / C} & =\begin{cases}
            0.5 &\lambda_c \leq-0.5  \\
            0.5-\left(\lambda_c+0.5\right) &  -0.5<\lambda_c<-0.3\\
            0.3 & \lambda_c \geq-0.3
        \end{cases}
    \end{aligned}
\end{equation}

I hope it's clear enough, it's the first time i use this forum. The image shows what I want to obtain. This is what i want to obtain

2 Answers 2

2

As starting point:

enter image description here

I consider nly first two cases in your MWE (Minimal Working Example), other you can rewrite on showed way yourself. By use of array environments inside of `split˙:

\documentclass{article}
\usepackage{amsmath}

\begin{document}
\begin{equation}
    \begin{split}
\alpha^{S/C} & = \left\{%
    \begin{array}{l @{\qquad} rl}
0                                       &    \lambda_c    & \leq - 1.95  \\
0.3+0.4\left(\lambda_c+1.2\right)       & -1.95<\lambda_c & <0.55        \\
1                                       &    \lambda_c    & \geq 0.55    \\
        \end{array}\right.    \\[1ex]
\mu_1^{S / C} & = \left\{%
    \begin{array}{l @{\qquad} rl}
                                -0.6    &       \lambda_c   & \leq-1.1       \\
-0.6-0.318\left(\lambda_c+1.1\right)    &           -1.1    & <\lambda_c<0   \\
                                -0.95   &       \lambda_c   & \geq 0
        \end{array}\right.    \\[1ex]
    \end{split}
\end{equation}
\end{document}
2

You can define a suitable environment. Here I define cases+ that takes as argument the width of the two columns it defines. Some visual formatting is needed (it might be made automatic, but…).

\documentclass{article}
\usepackage{amsmath}
\usepackage{array}

\newenvironment{cases+}[1]{%
  \left\{
  \renewcommand{\arraystretch}{1.2}% like cases does
  \begin{array}{@{}w{l}{#1}@{}w{r}{#1}@{}}
}{\end{array}\right.\kern-\nulldelimiterspace}
\newlength{\mytemplen}

\begin{document}

\begin{equation}
\setlength{\mytemplen}{10em}% adjust to suit
\begin{aligned}
\alpha^{S / C} &=
\begin{cases+}{\mytemplen}
  0 & \lambda_c \leq-1.95 \\
  0.3+0.4(\lambda_c+1.2) & -1.95<\lambda_c<0.55 \\
  1 & \lambda_c \geq 0.55
\end{cases+} \\ 
\mu_1^{S / C} &=
\begin{cases+}{\mytemplen}
  -0.6 & \lambda_c \leq-1.1 \\
  -0.6-0.318(\lambda_c+1.1) & -1.1<\lambda_c<0 \\
  -0.95 & \lambda_c \geq 0
\end{cases+} \\
\sigma_1^{S / C} &=
\begin{cases+}{\mytemplen}
  0.1 & \lambda_c \leq-1.3 \\
  0.1+0.2(\lambda_c+1.3) & -1.3<\lambda_c<-0.3 \\
  0.3 & \lambda_c \geq-0.3
\end{cases+} \\
\mu_2^{S / C} &=
\begin{cases+}{\mytemplen}
  -1.2 & \lambda_c \leq-0.7 \\
  -1.2-1.333(\lambda_c+0.7) & -0.7<\lambda_c<-0.1 \\
  -2.0 & \lambda_c \geq-0.1 \\
\end{cases+} \\
\sigma_2^{S / C} &=
\begin{cases+}{\mytemplen}
  0.5 &\lambda_c \leq-0.5  \\
  0.5-(\lambda_c+0.5) &  -0.5<\lambda_c<-0.3\\
  0.3 & \lambda_c \geq-0.3
\end{cases+}
\end{aligned}
\end{equation}

\end{document}

enter image description here

Note. I got rid of all the unnecessary \left and \right bits. Don't use them indiscriminately.

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