I have to split a quite long formula. I used a nested split environment but I have to break curly braces from one line to another using \right.
and \left.
The curly braces I get have different dimensions. I tried using \Biggl and \Biggr but they are too small. Here is my source:
\begin{equation}
\label{eq:splitted}
\begin{split}
c(x, y, t) &= \frac{M/Y}{b\sqrt{4\pi\left(\D_x^T+\K_x\right)t}}
\exp\left[-\frac{\left(x-Ut-x_0\right)^2}{4\left(\D_x^T+\K_x\right)t}\right]\\
&\begin{split}\frac{b}{\sqrt{4\pi\left(\D_y^T+\K_y\right)t}}
\left\{
\sum_{j=-\infty}^{\infty}%
\exp\left[-\frac{\left(y-y_0+2jb\right)^2}{4\left(\D_y^T+\K_y\right)}\right]\right.&%
\\ + \left.%
\exp\left[-\frac{\left(y+y_0+2jb\right)^2}{4\left(\D_y^T+\K_y\right)}\right]\right\}&
\end{split}
\end{split}
\end{equation}
Best Answer
No need of
\phantom
andsplit
; the best approach in this case is with themultlined
environment provided bymathtools
.Notice that I've removed all
\left
and\right
before the inner parentheses: they aren't needed and add spacing.By choosing
\biggl[
and\biggr]
instead of\left[
and\right]
we get uniform height of the brackets and we can use also the same size for the braces. In general, when a summation has limits above and below,\biggl
and\biggr
are to be preferred to\left
and\right
that produce too large symbols.The wrapping
gathered
environment is used for getting the equation number centered with respect to the whole formula.A refinement can be obtained by seeing that the two square root symbols are different though they contain similar formulas. If the second one is typed as
the result will be