General ⇒ Box around equations spanning several lines?

[nrqed]

How can one draw a box around multiline equations?
For single line equations, \boxed works great. But I haven't been able to figure out how to use it for multiline equations. Is there any way to use \boxed then? Or any other method?


Thanks!

[balf]

The empheq package, from the mh bundle, can do that, and much more.

B.A.

[Juanjo]

Thanks, balf, for bringing to my attention the empheq package. I didn't know it. After a quick review, it seems great and very useful. Anyway, there are simple alternatives to frame multiline formulas provided that they are not numbered or there are just one centered equation number for the whole set of formulas. For example, we can frame the formulas

Code: Select all

\begin{align*}
   E&=mc^2 \\
   b^2&=a^2+2\int_a^b x\,dx
\end{align*}

by writing

Code: Select all

\begin{equation*}
   \boxed{
   \begin{aligned}
      E&=mc^2 \\
      b^2&=a^2+2\int_a^b x\,dx
   \end{aligned}
   }
\end{equation*}

Compare also the following groups of formulas.

Code: Select all

\begin{gather}
   E=mc^2 \notag \\
   b^2=a^2+2\int_a^b x\,dx \\
   (a+b)^n=\sum_{k=0}^n\binom{n}{k}a^{n-k}b^k \notag
\end{gather}

\begin{equation}
  \addtolength{\fboxsep}{5pt}
   \boxed{
   \begin{gathered}
      E=mc^2 \\
      b^2=a^2+2\int_a^b x\,dx \\
      (a+b)^n=\sum_{k=0}^n\binom{n}{k}a^{n-k}b^k
   \end{gathered}
   }
\end{equation}

This example also shows how to add some space between the frame and the formulas.

[nrqed]

Thanks! The empheq package of the mh bundle does exactly what I need.

But I still need help. I have downloaded and extracted the mh bundle on my (Windows) machine. I have MikTeX 2.5 and TeXnicCenter installed. What must I do so that I can start using the empheq package in TeXnicCenter? I don't know where to put my mh bundle and what to do so that I will be able to use empheq in TeXnicCenter.

Thanks again.

[nrqed]

Thanks, balf, for bringing to my attention the empheq package. I didn't know it. After a quick review, it seems great and very useful. Anyway, there are simple alternatives to frame multiline formulas provided that they are not numbered or there are just one centered equation number for the whole set of formulas. For example, we can frame the formulas

Code: Select all

\begin{align*}
   E&=mc^2 \\
   b^2&=a^2+2\int_a^b x\,dx
\end{align*}

by writing

Code: Select all

\begin{equation*}
   \boxed{
   \begin{aligned}
      E&=mc^2 \\
      b^2&=a^2+2\int_a^b x\,dx
   \end{aligned}
   }
\end{equation*}

Compare also the following groups of formulas.

Code: Select all

\begin{gather}
   E=mc^2 \notag \\
   b^2=a^2+2\int_a^b x\,dx \\
   (a+b)^n=\sum_{k=0}^n\binom{n}{k}a^{n-k}b^k \notag
\end{gather}

\begin{equation}
  \addtolength{\fboxsep}{5pt}
   \boxed{
   \begin{gathered}
      E=mc^2 \\
      b^2=a^2+2\int_a^b x\,dx \\
      (a+b)^n=\sum_{k=0}^n\binom{n}{k}a^{n-k}b^k
   \end{gathered}
   }
\end{equation}

This example also shows how to add some space between the frame and the formulas.

Neat!!!!

Thanks for posting this!!

[localghost]

[...] Anyway, there are simple alternatives to frame multiline formulas provided that they are not numbered or there are just one centered equation number for the whole set of formulas. [...]

Using the empheq package looks much more simpler to me. Nevertheless it is good to know that there are alternatives.


Best regards
Thorsten

[balf]

You shouldn't download any package that is in The MiKTeX distribution (that is, almost every package): you download and install it with miktex's package manager (mpm). For other packages: you should install them manually, respecting the TDS hierarchy, preferably in a TeXMFlocal directory (declared as the root of a texmf hierarchy via miktex'ssettings). Here's an example: shortlst is not a part of miktex. I've installed:
-- shortlst.sty in ...\TeXMFlocal\tex\latex\shortlst\
-- the docs in ...\TeXMFlocal\doc\latex\shortlst\
and then refreshed the FNDB with miktex's settings.

Btw, miktex 2.5 should now be updated to miktex 2.7! It is not supported any more.

Regards,
B.A.