# LaTeX

LaTeX is a typesetting language used primarily to type mathematical expressions in an elegant fashion. For example, without LaTeX, $\frac{35}{137}$ would have to be written as 35/137. To use LaTeX in the forums, enclose your LaTeX code with dollar signs: $your codes here$. To use LaTeX on AoPSWiki, enclose your code with math tags instead of dollar signs, like so: $your codes here$

CHANGE: Dollar signs can now be used to use LaTeX.

## Useful Codes

\boxed{Answer} produces a box around your Answer. Cannot be used in Wiki

\frac{a}{b} produces a fraction with numerator $a$ and denominator $b$. $\frac{a}{b}$

^\circ produces the degrees symbol. $a^{\circ}$

\text{Your Text Here} produces text within LaTeX. $\mbox{Your Text Here}$. Cannot be used in the Wiki.

\mbox{Your Text Here} Produces text within LaTeX; can be used in the Wiki. $\mbox{Your Text Here}$

\sqrt{x} produces the square root of $x$. $\sqrt{x}$

\sqrt[n]{x} produces the $n$th root of $x$. $\sqrt[n]{x}$

a\equiv b \pmod{c} produces $a$ is equivalent to $b$ mod $c$. $a\equiv b \pmod{c}$ See Modular Arithmetic

\binom{9}{3} produces 9 choose 3. Cannot be used in Wiki.

{n}\choose{r} produces n choose r. ${n}\choose{r}$

x^{y} produces x to the power of y. $x^y$

x_{y} produces x with y in subscript. $x_y$

\rightarrow produces an arrow to the right. $\rightarrow$

\leftarrow produces an arrow to the left. $\leftarrow$

\uparrow produces an arrow pointing upwards. $\uparrow$

\downarrow produces an arrow pointing downwards. $\downarrow$

\updownarrow produces an arrow pointing up and down. $\updownarrow$

\ge produces a greater than or equal to sign. $\ge$

\le produces a less than or equal to sign. $\le$

\not> produces a not greater than sign. $\not>$

\not< produces a not less than sign. $\not<$

\not\ge produces a not greater than or equal to sign. $\not\ge$

\not\le produces a not less than or equal to sign. $\not\le$

\neq produces a not equal to sign. $\neq$

\infty produces an infinity sign. $\infty$

\perp produces a perpendicular sign. $\perp$

\angle produces an angle sign. $\angle$

\triangle produces a triangle. $\triangle$

\ldots produces three dots at the bottom of a line (ellipsis). $\ldots$

\cdots produces three dots in the middle of a line (as in a series sum or product). $\cdots$

Note that on AoPSWiki, many codes that work on the AoPS forums do not work. Also, a helpful tip is that if LaTeX fails to render within AoPSWiki, try adding the code \displaystyle to the beginning of the string of LaTeX. This often fixes minor rendering problems.

Also note that you do not have to use braces, "{" and "}", when you only want one character in the operation.

### Examples

• x^y is the same as x^{y}. $x^y$
• x_y is the same as x_{y}. $x_y$
• BUT x^10 is not the same as x^{10}. $x^10$ instead of $x^{10}$.

## Fonts

### Font families

• Roman (default): \textrm{...}
• Sans-serif: \textsf{...}
• Monospace (typewriter): \texttt{...}

### Font sizes

To activate a font size, write '{\tiny{This text is tiny}}', for example.

• \tiny (5 pt.)
• \scriptsize (7 pt.)
• \footnotesize (8 pt.)
• \small (9 pt.)
• \normalsize (10 pt.)
• \large (12 pt.)
• \Large (14 pt.)
• \LARGE (18 pt.)
• \huge (20 pt.)
• \Huge (24 pt.)

### Font styles

• Bold \textbf{...}
• Italics \textit{...}
• Slanted \textsl{...}
• Small capitals \textsc{...}
• Sans-serif \textsf{...}
• Monospace \texttt{...}
• Emphasis \emph{...}

## Tutorials & Tools

This article is a tutorial about the AoPSWiki or AoPS Forum.

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