# Help:Math

This wiki uses the Math extension, version 1.2.

• Math markup is handled by the LaTeX typesetting system and rendered by texvc (by default).
• Indent block equations with a colon (see examples below).
• Mediawiki will render HTML characters for short equations, and PNG images for longer ones.
• display="inline" renders the equation inline.
• display="block" renders the equation centered in a paragraph of its own. Please don't use this on the SEG Wiki.

## Examples

Example short equation: ${\displaystyle E=mc^{2}}$

Example short equation with forced image rendering, using a space at the end of the equation:

${\displaystyle E=mc^{2}\ }$

Longer equations render as images regardless; here's the Aki-Richards equation:

${\displaystyle R_{\mathrm {PP} }(\theta )={(1+\tan ^{2}\theta )\,{\frac {\Delta I_{\mathrm {P} }}{2I_{\mathrm {P} }}}}\ \ -\ \ {8\left({\frac {V_{\mathrm {S} }}{V_{\mathrm {P} }}}\right)^{2}\sin ^{2}\theta \,{\frac {\Delta I_{\mathrm {S} }}{2I_{\mathrm {S} }}}}\ \ -\ \ {\left[{\frac {1}{2}}\tan ^{2}\theta -2\left({\frac {V_{\mathrm {S} }}{V_{\mathrm {P} }}}\right)^{2}\sin ^{2}\theta \right]{\frac {\Delta \rho }{\rho }}}}$

We can also add id="aki-richards" to the opening math tag, and get a link to that equation. Now we can refer to the Aki-Richards equation as a link on this page. The equation doesn't get a number or anything, just an invisible link.

## Options

A new feature is the ability to control display vs inline rendering. For example, we can ask for an equation inline like so:

<math display="inline">\sum_{i=0}^\infty 2^{-i}[/itex]

Which gives us this version: ${\textstyle \sum _{i=0}^{\infty }2^{-i}}$. The idea is that the next line height is not disturbed by large operators (notice the arrangement of the limits).

We can ask for an equation block like so (notice no colon):

<math display="block">\sum_{i=0}^\infty 2^{-i}[/itex]


Which gives us this version:

${\displaystyle \sum _{i=0}^{\infty }2^{-i}}$

As opposed to the 'old' style, where we don't specify a display style...

${\displaystyle \sum _{i=0}^{\infty }2^{-i}}$

## Style

• Constants and names or label are roman (i.e. upright, not italic): VP. Use \mathrm{P} in LaTeX math.
• Pi, e, the differential d, and lots of other symbols are usually roman
• Variables are italic (the default character style in LaTeX math)
• Vectors are roman and bold (use \mathbf{} — it's best to avoid \vec{}, which uses the arrow notation)
• Use the built-in LaTeX functions for \sin, \log, etc.