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When I write something like \dot{\mathbf{J}}=\mathbf{r}\times -\frac{k}{r ^3} \mathbf{r}, it renders as

enter image description here

This looks alright, but the dot above the $J$ looks slightly too far to the left. I would have thought the dot should be horizontally centred, so as to be half-way along the horizontal bar at the top of the $J$.

So, should it be centred, and if so, how do I do this?

GibbNotGibbs
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  • \skew{2}\dot{\mathbf{J}} or some number giving a result you like. BTW the formula doesn't look right... – campa Oct 22 '23 at 17:49
  • The dot is centered over the J if you include the whole letter. OTOH, without \mathbf the dot is much firther to the right. – John Kormylo Oct 22 '23 at 18:23
  • @campa Thanks for the suggestion. As for the "formula", it's not supposed to be true for a general force. I'm using the potential $V=k/r$ where $r=|\mathbf{r}|=(x^2+y^2+z²)^{1/2}$. (And I'm taking mass to be constant.) – GibbNotGibbs Oct 22 '23 at 19:30
  • You can solve with this link: https://tex.stackexchange.com/questions/315181/dot-over-a-not-in-the-right-place – Sebastiano Oct 22 '23 at 19:46
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    I was referring to the minus sign after the cross product without parentheses – campa Oct 22 '23 at 20:15
  • It seems a duplicate of https://tex.stackexchange.com/questions/457983/dot-with-only-operator-overline – Sebastiano Oct 22 '23 at 20:57
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    @Sebastiano Yes and no. In your question the overline was the issue, here it's different. (Oh boy, I wrote a bad answer there :-).) – campa Oct 22 '23 at 21:00
  • @campa Now change it – Sebastiano Oct 22 '23 at 21:02
  • @campa Wdym? Afaik, if you have vectors $u,v$ and a scalar $\sigma$, then $(\sigma u)\times v=u\times (\sigma v)=\sigma(u\times v)$, so it doesn't matter where the brackets go. – GibbNotGibbs Oct 22 '23 at 22:28
  • Yes, but not with a minus. It should be \vec{r} \times (- ...), not \vec{r} \times - ... – campa Oct 23 '23 at 07:22
  • @campa I'm quite confused. What difference does it make? I'm not aware of there being any other interpretation of what I've written. (I assume you mean it's a mathematical error and not a typesetting error.) – GibbNotGibbs Oct 24 '23 at 22:55

1 Answers1

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(I could swear this is a duplicate but I can't find it...)

TeX tries its best to place math accents but sometimes it's not perfect. That's where the macro \skew comes in handy: the first argument in a number (in math units), the second is a math accent:

\documentclass{article}
\begin{document}
$\dot{\mathbf{J}}$
$\skew{2.5}\dot{\mathbf{J}}$
\end{document}

enter image description here

campa
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