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Greetings LaTeX Masters!

In the code below, I'm trying to align the solution steps on the equal sign. The alignment works until I get to the final step where I draw a box around the solution. This line of code doesn't draw the box:

\boxed{x&=2} and crashes the compiler.

Without the &, the solution box doesn't align.

[![Mis-aligned solution box][1]][1]

\documentclass{article}
\usepackage{mathtools}
\usepackage{amsmath}
\begin{document}

Trapezoids: Median line formula\


%\setcounter{equation}{2}
\begin{equation}
\setlength{\jot}{8pt}
    \begin{aligned}
    Median &= \dfrac{1}{2}(top + bottom)\
    3x+1&=\dfrac{(2x+1)+(2x+5)}{2}\
    2\cdot (3x+1)&=\Biggl(\dfrac{(2x+1)+(2x+5)}{2}\Biggr) \cdot \dfrac{2}{1}\
    6x+2&=4x+6\
    6x&=4x+4\
    2x&=4\
  \boxed{x=2}
    \end{aligned}
\end{equation}


\end{document} ```
Siuslaw Math
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1 Answers1

3

See How to make a box around an equation in align-environment

You can't use directly stuff like \yourcommand{a & b} or LaTeX will think that the & symbol might be use for something else inside the \yourcommand macro. For instance, \yourcommand could be a shortcut to create an array.

You can use \Aboxed{…} from mathtools.

\documentclass{article}
\usepackage{mathtools}
\usepackage{amsmath}
\usepackage{mathtools}
\begin{document}

Trapezoids: Median line formula\


\begin{align}
  Median &= \dfrac{1}{2}(top + bottom)\
  3x+1&=\dfrac{(2x+1)+(2x+5)}{2}\
  2\cdot (3x+1)&=\Biggl(\dfrac{(2x+1)+(2x+5)}{2}\Biggr) \cdot \dfrac{2}{1}\
  6x+2&=4x+6\
  6x&=4x+4\
  2x&=4\
  \Aboxed{x&=2}

\end{align}


\end{document}
tobiasBora
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  • thanks so much for providing a solution I never would have found on my own! Question marked "solved" – Siuslaw Math Apr 03 '23 at 19:52
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    @SiuslawMath By the way, you might prefer to simply use \begin{align} instead of nesting equation and aligned. – tobiasBora Apr 03 '23 at 20:00
  • So I removed \begin{equation} and ```\end{equation} as suggested (assuming I followed instructions correctly). But now I get a "not in math mode" error. Note: The mwe code has been revised to reflect this change. – Siuslaw Math Apr 03 '23 at 20:07
  • @toabiasBora Sorry. I initially didn't see that you had revised mwe code in the OP. Thanks for doing that! – Siuslaw Math Apr 03 '23 at 20:09
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    @SiuslawMath you also need to remove the ed in the aligned (see my edit, in my first answer I only fixed the indentation). – tobiasBora Apr 03 '23 at 20:48
  • @toabiasBora Yes, I now see align vs aligned. What is causing the enumeration of the solution steps on the right side? Thank you! – Siuslaw Math Apr 03 '23 at 21:14
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    @SiuslawMath if you don't want the enumeration on the right, you can use the star version \begin{align*}…\end{align*}. Enumeration is useful to refer to the equations later. – tobiasBora Apr 03 '23 at 21:29
  • ah, yes, forget about {align*}. For my high school algebra classes, usually I use enumeration to number each problem in the problem set. But your point is well taken! – Siuslaw Math Apr 03 '23 at 21:45