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LaTex advice/help

  1. Oct 3, 2011 #1
    Hi all

    I use Lyx v1.65 for creating LaTex.

    Obviously it displays OK in Lyx. It also displays OK with an online editor I've tried
    http://www.codecogs.com/latex/eqneditor.php

    But invariably when I try to post LaTex to this forum it does not work. I've tried the sandbox which the reason for the error, but frankly speaking I don't have time to play around with LaTex code directly.

    I wonder if anyone can suggest a good LaTex editor that is compatible with this forum.

    FWIW, here's some LaTex created in Lyx which does not work here

    \mathbf{\boldsymbol{\beta}^{\textrm{T}}A\boldsymbol{\beta}}&=\overset{n}{\underset{i=1}{\sum}}\overset{n}{\underset{j=1}{\sum}}\beta_{i}a_{ij}\beta_{j}

    and

    \frac{\partial(\mathbf{\mathbf{\beta}^{\textrm{T}}}\mathbf{A\boldsymbol{\beta}})}{\partial\beta_{k}}&=2\beta_{k}a_{kk}+2\overset{n}{\underset{i\neq k}{\sum}}a_{ki}\beta_{i}

    Thanks
    LR
     
  2. jcsd
  3. Oct 3, 2011 #2

    Fredrik

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    When you type 50 characters without a space, vBulletin will insert a space that usually breaks the code. Here you can see how it breaks the word "boldsymbol":

    [tex]\mathbf{\boldsymbol{\beta}^{\textrm{T}}A\boldsymbol{\beta}}&=\overset{n}{\underset{i=1}{\sum}}\overset{n}{\underset{j=1}{\sum}}\beta_{i}a_{ij}\beta_{j}[/tex]

    The workaround is to type a few extra spaces. That won't be enough in this case, unless you also put it in an align environment (because of the & symbol).

    \begin{align}\mathbf{\boldsymbol{\beta}^{\textrm{T}} A\boldsymbol{\beta}} &=\overset{n}{\underset{i=1}{\sum}} \overset{n}{\underset{j=1}{\sum}} \beta_{i}a_{ij}\beta_{j}\end{align}
     
  4. Oct 3, 2011 #3
    Hi Fredrik

    Thanks so much for the explanation !

    So, just to be clear if I put
    begin{align}
    end{align}
    around the text from Lyx, it should solve the problem ?

    Thanks again
    LR
     
    Last edited: Oct 3, 2011
  5. Oct 3, 2011 #4

    Fredrik

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    No. That only ensures that the symbols & and \\ will be understood. To avoid the 50-character feature, you have to type extra spaces where they do no harm (at least one space every 50 characters).

    It seems weird to me that Lyx gives you code that contains & and \\, but not the code to begin and end an align environment (or some other environment that understands those codes). That shouldn't work anywhere.
     
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