Parenthesis Size in a multiline equation

How can I use

\left(.... \right)

which automatically adjust size of parenthesis with it's inside content, in a multiline equation in

\begin{align} and

environment.

• you can't. Instead use \biggl( ... \\  .. \biggr) or whatever size you need. – David Carlisle Apr 15 '15 at 7:22
• @DavidCarlisle Thanks!, I know about this, but I need parenthesis bigger than \Biggl(, also this doesn't adjust parenthesis size with its inside content! – QGravity Apr 15 '15 at 7:36
• you really need huge parens on one line of a multiline display? strange:-) The definition of \big and friends is only a single line each so it is easy to make a bigger one if needed. It doesn't adjust automatically but that's just how it is, – David Carlisle Apr 15 '15 at 8:18

You can, as documented in mathtools, thanks to a code by Sébastien Gouezel (§3.6.1 of the doc):

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{mathtools}
\usepackage{lmodern}

\newcommand\MTkillspecial[1]{% helper macro
\bgroup
\catcode\&=9
\let\\\relax%
\scantokens{#1}%
\egroup
}
\DeclarePairedDelimiter\brparen
\lparen\rparen
\reDeclarePairedDelimiterInnerWrapper\brparen{star}{
\mathopen{#1\vphantom{\MTkillspecial{#2}}\kern-\nulldelimiterspace\right.}
#2
\mathclose{\left.\kern-\nulldelimiterspace\vphantom{\MTkillspecial{#2}}#3}}

\begin{document}
A =\! \begin{aligned}[t] \brparen[\Big]{& a + B + c + d + e{} \\ & + f +g + h}\ \end{aligned}

A =\! \begin{aligned}[t] \brparen*{& \frac{K^2}{L^2} + B + + C + D + E\\ & + F + G + H} \end{aligned}
\end{document}
`