# [LON-CAPA-users] Algebra Expression Rendering in LON-CAPA

Damien Guillaume damieng at msu.edu
Tue Jan 17 11:29:18 EST 2017

You have to use eval="true" for <m> if you have variables inside. And
make sure the display is using MathJax.

Try this:

<m eval="on" display="mathjax">$$\frac{numer}{denom} \left[ \pi + \sum_{n=1}^{\infty} \frac{sum_numer}{sum_denom_n_coeff n - sum_denom_const} \cdot \sin(w nt) \right]$$</m>

If you put the whole expression into a variable, you will also have to
escape the "\" with "\\".

Damien

> Hi Damien,
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>
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> Thanks for your reply. At least now I know that I was chasing the wind. I was able to get close by using Sigma in place of sum in the expression, but then only the "n" was subscripted, not the "=1" part, even though I used braces: _{n=1}...
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>
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> I had initially tried to render the equation in the xml portion of the problem, but when I did that I had a lot of trouble properly displaying some of the variables using the <m>$...$</m> command. It worked in some places but not others.
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> This is as close as I have been able to get to a proper expression:
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> [cid:image001.png at 01D26DF0.DF719FF0]
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> In the xml portion I have been able to render it nicely:
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> [cid:image002.png at 01D26DF6.82F21010]
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> ...but only if I hard-code the constants in the two fractions and inside the sine. Is there a way to display variable values from the perl script in place of the constants? I have tried a few things, but all were unsuccessful.
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> Thanks,
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>
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> Gene L. Harding, PE
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> Associate Professor of ECET
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> 574-520-4190
>
> Purdue University-South Bend