horizontal alignmentmath-modesymbols
I write the codes below to get a square as if to say q.e.d.
$$equation$$\textbox{\hfill\square}
Text\textbox{\hfill\square}
I want the square at the right extreme of the same line. I succeed only when the rest of the line has text and/or an equation within $ $, but not when it has an equation within $$ $$. In this case the square appears in the extreme right but in the next line but I want it on the same line.
Any help is appreciated.
Besides the balancing issue associated to the use of \left, \right, your expression can be improved introducing some modifications:
\left( ... \right) for the inner expressions produces delimiters that are too big and introduce some additional horizontal space that it's superfluous in this particular case, so I think that it's better to use just (...).+{} so that the ending plus sign in the first line is correctly trated as an operator; analogously, you need to use {}+ for the first plus sign in the second line.\left[, \right. in the first line and \right., \left] in the second line, I would suggest you to use \bigl[, \bigr] which don't need to be balanced in each line and produce better sized delimiters in most cases.In the following code I include, for comparison, your code (with the balancing problem solved) and then the code implementing my suggestions:
\documentclass[12pt]{article}
\usepackage[margin=2cm]{geometry}% just for the example
\usepackage{amsmath}
\begin{document}
\begin{equation}
\begin{split}
MSE_{II}(\overline{y}_{CST}) &= MSE_{I}(\overline{y}_{CST})
+\overline{Y}^{2}\left[ \left( c_{2}^{2}+2c_{1}c_{3} \right)V_{4,\, 0}+2c_{1}c_{2}V_{3,\,0}
+2\left(2c_{1}c_{2}+c_{3}\right)V_{3,\, 1} + \right. \\
& \left. + 2 \left(c_{1}^{2}+c_{2} \right)V_{2,\, 1}+ \left(c_{1}^{2}+2c_{2} \right)V_{2,\, 2}
+ {2c_{1}V_{1,\, 2}} \right]
\end{split}
\end{equation}
\begin{equation}
\begin{split}
MSE_{II} ( \overline{y}_{CST} ) &= MSE_{I} ( \overline{y}_{CST} )
+ \overline{Y}^{2} \bigl[ (c_{2}^{2} + 2c_{1}c_{3} ) V_{4,\, 0} + 2c_{1}c_{2} V_{3,\,0}
+ 2 ( 2c_{1}c_{2} + c_{3} ) V_{3,\, 1} +{} \\
&\qquad {}+ 2 ( c_{1}^{2} + c_{2} )V_{2,\, 1} + ( c_{1}^{2} + 2c_{2} ) V_{2,\, 2}
+ {2c_{1}V_{1,\, 2}} \bigr]
\end{split}
\end{equation}
\end{document}
Change the order, this works just fine, amsthm after amsmath, otherwise it might be a bit hard for it to hook into align*
\documentclass[a4paper]{article}
\usepackage{amsmath}
\usepackage{amsthm}
\interdisplaylinepenalty=2500
\usepackage{amssymb}
\usepackage{hyperref}
\title{Example to Show QED is Misplaced}
\author{}
\begin{document}
\begin{proof}
This proof is typeset correctly:
\begin{equation*}
x = y + z \qedhere
\end{equation*}
\end{proof}
\begin{proof}
But this one not!
\begin{align*}
x & = u + v \\
& = y + z \qedhere
\end{align*}
\end{proof}
\end{document}
Best Answer
Use
amsthmand itsproofenvironment. If a proof ends with a displayed equation,itemizeorenumerate, use\qedherein the last line.Example:
Never use
$$...$$in LaTeX, see Why is \[ ... \] preferable to $$ ... $$?