Double braces in equation

Question

I'm trying to create the attached image formulae. But I don't know how to get the double braces to work. This is my attempt with only single brace.

    x(t_n) = \left\{ \begin{array}{l l}
  0      &\quad \mbox{ $n<ns$ or $n>ne$} \\
  x(t_n) &\quad \mbox{ $ns\leq n\leq ne$}
\end{array} \right.

Could someone help me with the second brace? Thanks in advance

Answer 1

I would try cases in amsmath.

 \begin{equation}
    x(t_n) = \begin{cases}
        0 \\
        x(t_n) 
    \end{cases}
    \xi(t_n) = \begin{cases}
        0      &n<ns, n>ne \\
        \xi(t_n) &ns\leq n\leq ne$
    \end{cases}
\end{equation}

Answer 2

\documentclass{minimal} \usepackage{amsmath}
\begin{document}
\[ x(t_n) =\begin{cases} 0\\x(t_n)  \end{cases}\quad
\xi(t_n)=\begin{cases} 0 & \qquad\qquad (n<ns, n>ne) \\
\xi(t_n) & \qquad\qquad (n\leq n\leq ne) 
\end{cases}\]
\end{document}