How to make \left, \right pairs of delimiter work over multiple lines?

Question

I have a very long equation that must be separated into two lines, and it has several pairs of nesting \left \right delimiters. Unfortunately, it seems that they need to be on the same line in order for them to work.

Also I'm using the align environment because I need the aligning functionality. Is there a way to have the size of delimiters automatically adjusted over multiple lines?

Answer 1

The breqn package is a package that defines a set of new math environments, with the purpose of enabling automatic line breaking of displayed math. These new environments also let you have \left and \right on different lines, though it is not the main goal of the package.

Note that the package has several known problems and incompatibilities, so depending on your use case it might not be for you. I recommend a look at the manual.

---

The example below is one where you definitely shouldn't use \left and \right in the first place, but it serves to illustrate that it works. The dmath environment is similar to equation.

\documentclass{article}
\usepackage{geometry}
\geometry{a5paper, margin=5cm}

\usepackage{breqn}
\begin{document}
Automatic breaking:
\begin{dmath}
55 - \left(1+2+3+4+5+6+7+8+9+10\right) = 0
\end{dmath}

Manually breaking a line seems to work as well:
\begin{dmath}
55 - \left(1+2+3+4+\\5+6+7+8+9+10\right) = 0
\end{dmath}
\end{document}

Answer 2

You can't.

You can use some thing like \biggl, \biggr, or \left.\vphantom{...}\right). For example:

\[
\begin{split}
a &= \left( \frac12 + \frac13 + \frac14 \right. \\
  &\quad \left. {}+ a + b + c \vphantom{\frac12}\right)
\end{split}
\]

Answer 3

The solution for me was to use virtual dot delimiters

\frac{\partial F}{\partial x} &= \left[ \frac{\partial y}{\partial z} \right. \\
                              &* \left. \frac{\partial z}{\partial x} \right]

which was the comment posted by percusse in this question which was marked as a duplicate.

The virtual dot delimiters are in Leo Liu's answer above, but a TeX n00b like me wouldn't have seen it.

FYI Sphinx-1.1.3 already supports multi-line math with the math directive using the AmSMath LaTeX package, i.e. breqn is not necessary.

Answer 4

Have a look at the nath package.

Answer 5

I had the same problem. I wanted to show this equation

\begin{equation*}
    V_{sal} = -\left(1.V_8 + \frac{1}{2}.V_7 + \frac{1}{8}.V_6 +\frac{1}{8}.V_5  + \frac{1}{16}.V_4 \right.\\
     \left. + \frac{1}{32}.V_3 + \frac{1}{64}.V_2 + \frac{1}{128}.V_1\right) 
\end{equation*}

but since it is too long (in a two column document), I used multline enviroment but it gives an error (something like Missing \right. inserted. \end{multline*} or Extra \right. \end{multline*}). I solved it with this new code

\begin{multline*}
V_{sal} = -\left(1.V_8 + \frac{1}{2}.V_7 + \frac{1}{8}.V_6 +\frac{1}{8}.V_5  + \frac{1}{16}.V_4 \right.\\
 \left. + \frac{1}{32}.V_3 + \frac{1}{64}.V_2 + \frac{1}{128}.V_1\right) 
\end{multline*}

Note that I added a \right. at the end of the first row and \left. at the beginning of the second row.

Answer 6

The previous "automated" solutions all use certain packages that have compatibility issues with amsmath. Here is a sort-of-automated solution that does not require additional packages.

This solution uses \vphantom and is in essence the same as the previous answers using this command.

% split \left and \right across two lines
% use only between \[ and \] (modify as needed for \begin{equation}\end{equation}, etc.)
\newcommand\MatchBrackets[2]{\left[#1\vphantom{#2}\right.\]\[\left.\vphantom{#1}#2\right]}
\newcommand\MatchParentheses[2]{\left(#1\vphantom{#2}\right.\]\[\left.\vphantom{#1}#2\right)}

Usage:

\[\nabla h=\MatchParentheses{\int_0^{e^5}e^{-z^2}dz+\frac12\cdot\cos\left(\frac12\cdot x\right)\cdot\cos(y),}{-\frac12\cdot\cos\left(\cos\left(\frac12\cdot y\right)\right)\cdot\sin\left(\frac12\cdot y\right)-\sin(x)\cdot\sin(y)}\]

(Idea taken from Wintz's comment here. Example modified from zdim's answer here.)

Answer 7

I came here from this recent question on the same topic, and even if this is an old question, and even if it is likely a LaTeX question, I think it might be useful for some people to have a ConTeXt answer here.

Since a few years, displayed formulas in ConTeXt are typeset as paragraphs, which has made it possible to break inside \left \right constructions. Below I show an example with the formula from the question I arrived from.

We use align=slanted to have the first line flushed left and the last one flushed right (if there were more lines, they would be centered). We also use a margin. The \breakhere tells where to break the formula.

\starttext

\samplefile{knuthmath}

\startformula[align=slanted,margin=3em]
  P^^{ij}
  = -2 \sqrt{-g}
    \left\{
      G^^{ijlm} \dot K__{lm} + \alpha K^^{ij} K - \alpha g^^{ij} K__{lm} K^^{lm} +
      \alpha R^^{ij}^^^^{3} \breakhere
      - g^^{ij}
      \left[
        \left(
          \frac{\alpha}{3} + 2\beta
        \right)
        (R^^^^{3} - 3 K__{lm} K^^{lm} + K^^2) + \gamma
      \right]
    \right\}
  \numberhere[Pijsol]
\stopformula

We see in \in{Equation}[Pijsol] that \unknown

\stoptext

(The curious person can notice that ^^ and ^^^^ are used. They are used to denote indices (rather than powers or what-else). This can be useful in case of accessibility, and is not really important here.)

Answer 8

I recently wrote a longmath package that deals with the problem at the Lua level, so it works with lualatex.

It allows you to have delimiter groups over multiple lines, or link delimiters in different (sub)formulas to each other, automatically adapting their sizes to the content between them.

\documentclass{article}
\usepackage{longmath}
\usepackage{amsmath}
\begin{document}
\begin{align}
            x &= \lleft {label1} ( 1 + 2 + 3 \\
              &  \qquad + 4 + 5 + 6 + \frac{1}{2} \rright {label1} )
\end{align}
\end{document}

Here, label1 is a label that links the ( and ) to each other. They will have the same size, adapted to the fraction.