Math & Science ⇒ Serious Multiline Equation Issues

[Ehresmann]

For some reason, I cannot get the /begin{cases} command to compile my sequence with cases correctly. I have looked on many different resources and have tried many different "minor tweakings", but my brace will not extend to both lines. It just remains center on the first line. Here is one of the things I have tried:

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$f_n(x) = \begin{cases} n & \mbox{ if } x \geq \\ 3n+1 & \mbox{ if } x<n \end{cases}$

[Stefan Kottwitz]

Hi Ehresmann,

welcome to the board!
You have to load the amsmath package:

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\usepackage{amsmath}

The standard LaTeX macro \cases has a different syntax.

Stefan

[Ehresmann]

I have already loaded amsmath and amssymb in the document.

[Stefan Kottwitz]

Just try this example:

Code: Select all

\documentclass[a4paper,10pt]{article}
\usepackage{amsmath}
\begin{document}
$f_n(x) = \begin{cases} n & \mbox{ if } x \geq \\ 3n+1 & \mbox{ if } x<n \end{cases}$
\end{document}

When I compile it the brace spans over two lines.

Stefan

[Ehresmann]

The code from above works when I put it in its own separate document. In the document I am working on, it doesn't work. I did a little copying and pasting into a new doc, and now everything seems happy. So, moral of the story, it now works, but I have no idea why.

Thanks for the help!

[Stefan Kottwitz]

That's an example where just copying one line of code to the forum is simply not enough. The best way for getting help would be to create a minimal working example starting from the original code.

If you reduce a copy of your code to a minimal but complete example I'm sure we would find the cause of the problem. Perhaps keep it in mind if further problems would occur - nearly all problems can be solved if they could be tested & reproduced.

Stefan