I am trying to use a big equation inside flalign. The biggest chunk is the third line and I couldn't figure out how to something akin to \shoveright
in this third equation, as I want is ending on the right margin. Does anyone know how I can do that in this code?
\documentclass[12pt]{article}
\usepackage{amsmath}
\usepackage[letterpaper]{geometry}
\begin{document}
\def\del{\, \mathrm{d}}
\def\inv{^{-1}}
\begin{flalign*}
&\del L_j= \beta_j^{-2}\left (\tilde{\Sigma}_j\inv+\tilde{\Sigma}_{wj}\inv+\Psi_j\inv +\rho^{-2}\sigma_x^2\Psi_j^{-2}\right )\inv\left\{\tilde{\Sigma}_j^{-3}\left (\Sigma_{\epsilon j}-\Sigma_j\right )\del \Sigma_j\right. & \\
&\phantom{\del L_j=} +\left[1+2\left (\tilde{\Sigma}_{wj}\inv+\Psi_j\inv +\rho^{-2}\sigma_x^2\Psi_j^{-2}\right )\Sigma_{\epsilon j}\right ]\del \tilde{\Sigma}_{wj}\inv &\\
& \left. +2\left[\left (\tilde{\Sigma}_{wj}\inv+\Psi_j\inv +\rho^{-2}\sigma_x^2\Psi_j^{-2}\right )\Sigma_{\epsilon j}\left (1+2\rho^{-2}\sigma_x^{-2}\Psi_j\inv\right )+\left (1+\rho^{-2}\sigma_x^{-2}\Psi_j\inv\right )\right ]\del \Psi_{j}\inv\right\}&\\
&\phantom{\del L_j}= \text{right-hand-side number 1}&\\
&\phantom{\del L_j}= \text{right-hand-side number 2}&\\
&\phantom{\del L_j}= \text{etc.} &
\end{flalign*}
\noindent
This text is just to show the left and right margins. This text is just to show the left and right margins.
\multlinegap=0pt
\begin{multline*}
\del L_j= \beta_j^{-2}\left (\tilde{\Sigma}_j\inv+\tilde{\Sigma}_{wj}\inv+\Psi_j\inv +\rho^{-2}\sigma_x^2\Psi_j^{-2}\right )\inv\left\{\tilde{\Sigma}_j^{-3}\left (\Sigma_{\epsilon j}-\Sigma_j\right )\del \Sigma_j\right. \\
+\left[1+2\left (\tilde{\Sigma}_{wj}\inv+\Psi_j\inv +\rho^{-2}\sigma_x^2\Psi_j^{-2}\right )\Sigma_{\epsilon j}\right ]\del \tilde{\Sigma}_{wj}\inv\\
\shoveright{\left. +2\left[\left (\tilde{\Sigma}_{wj}\inv+\Psi_j\inv +\rho^{-2}\sigma_x^2\Psi_j^{-2}\right )\Sigma_{\epsilon j}\left (1+2\rho^{-2}\sigma_x^{-2}\Psi_j\inv\right )+\left (1+\rho^{-2}\sigma_x^{-2}\Psi_j\inv\right )\right ]\del \Psi_{j}\inv\right\}}\\
\shoveleft{\begin{aligned}
\phantom{\del L_j} &= \text{right-hand-side number 1}\\
\phantom{\del L_j} &= \text{right-hand-side number 2}\\
\phantom{\del L_j} &= \text{etc.}
\end{aligned}}
\end{multline*}
\noindent
This text is just to show the left and right margins. This text is just to show the left and right margins.
\end{document}
In the second attempt, the third equation ends at the right margin. The caveat is that the spacing between on equation and the next in the aligned
is not as large as the one in the previous code using align
, so I don't regard it as satisfactory.
Also, for some reason my compiler reports over and underfull boxes, even though I cannot see why.
Best Answer
Given the structure of the formula and the width of the text block, I don't think you can display the equation in fewer than four lines. This necessitates breaking some of the longer parenthetical terms across two or more lines.
By the way, not only do
\left
and\right
not work across broken lines, they arguably also choose math fences that are inappropriately large for the formula at hand. I suggest using\bigl
and\bigr
for the round parentheses and\Bigl
and\Bigr
for the square brackets and curly braces.Finally, I wouldn't use an
flalign
environment, asalign
seems to be perfectly up to the task.The thin lines in the screenshot are generated by the
showframe
option of thegeometry
package; drop this option in the production version of your paper.