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`\left`

& `\right`

Synopsis:

\leftdelimiter1... \rightdelimiter2

Make matching parentheses, braces, or other delimiters. The delimiters are sized according to the math they enclose. This makes a unit vector surrounded by appropriate-height parentheses.

\begin{equation} \left(\begin{array}{c} 1 \\ 0 \\ \end{array}\right)

Every `\left`

must have a matching `\right`

. Leaving out the
`\left(`

in the above gets ‘`Extra \right`’. Leaving off the
`\right)`

gets ‘`You can't use `\eqno' in math mode`’.

However, the two delimiters `delimiter1` and `delimiter2` need
not match. A common case is that you want an unmatched brace, as
below. Use a period, ‘`.`’, as a null delimiter.

\begin{equation} f(n)=\left\{\begin{array}{ll} 1 &\mbox{--if \(n=0\)} \\ f(n-1)+3n^2 &\mbox{--else} \end{array}\right. \end{equation}

Note that to get a curly brace as a delimiter you must prefix it with a
backslash, `\{`

.