I had set my preferences to use MathML, but I've just realised it fails to display square root of fractions correctly. With MathML, $$\sqrt{\frac{n-2}{1-r^2}}$$ looks almost the same as $$\frac{ \sqrt{n-2}}{1-r^2}$$ In particular, the square-root encloses only the numerator, which changes the interpretation of the formula

I'm using Firefox 3.6.10 under Windows XP Pro Service Pack 3. I selected MathML by right-clicking any displayed formula to display a context menu and selecting Settings => Math Renderer => MathML.

Apologies if this is a MathML problem rather than a StackExchange problem. I don't know where to raise MathML bugs though.

EDIT: Snip of screenshot as requested: wrongly displayed square-root of fraction under MathML

  • $\begingroup$ I'm unable to replicate, mind posting a pic of the problem? $\endgroup$
    – Andy W
    Commented Feb 21, 2011 at 2:16
  • $\begingroup$ The square root of the entire fraction in the first expression looks fine to me (FireFox 3.6.13 on Win 7/64). Exactly how was the screen shot generated? What browser, what OS, which Web page? $\endgroup$
    – whuber Mod
    Commented Feb 21, 2011 at 14:10

1 Answer 1


It's the fonts! I was able to replicate after I uninstalled these. Hence installing the fonts renders the formula correctly.

Via https://developer.mozilla.org/en/Mozilla_MathML_Project/Fonts

  • $\begingroup$ Many thanks Andy! I would have realised it was a font issue if it'd displayed question marks or boxes with hex numbers in, as that page appears to indicate. Displaying a reasonable-looking formula with a different meaning is more worrying. $\endgroup$
    – onestop
    Commented Feb 23, 2011 at 9:00
  • $\begingroup$ @onestop - I can't say I understand why that is the case, and Google Chrome behaves differently than Firefox whether or not the fonts are installed. $\endgroup$
    – Andy W
    Commented Feb 23, 2011 at 13:34

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