Number
$\frac{1}{2}$
\frac{1}{2}
\frac comes from "fraction". The first wave brackets is for the numerator and the second is for the denominator.
$\displaystyle \frac{1}{2}$
\displaystyle \frac{1}{2}
If you add "\displaystyle", it will be displayed larger.
$\dfrac{1}{2}$
\dfrac{1}{2}
\dfrac means \frac in \displaystyle.
$\require{physics} \flatfrac{1}{2}$
\require{physics} \flatfrac{1}{2}
\flatfrac in the physics extension allows you to write fractions on a line. You can also use the sign / to write "1/2".
$\left( -\frac{1}{2} \right)^2$
\left( -\frac{1}{2} \right)^2
To keep the fractions in parentheses, prefix the brackets with \left and \right.
$\require{physics} \qty( -\frac{1}{2} )^2$
\require{physics} \qty( -\frac{1}{2} )^2
\qty in the physics extension allows you to write parenthesized fractions a little simpler. \qty comes from physical quantity.
$\frac{a+b}{c+\frac{d}{e}}$
\frac{a+b}{c+\frac{d}{e}}
Fractions can be nested.
$\cfrac{a+b}{c+\cfrac{d}{e}}$
\cfrac{a+b}{c+\cfrac{d}{e}}
With \cfrac, the size of the fraction will be the same. \cfrac comes from continued fraction. Using \dfrac would produce a similar display.
$\begin{eqnarray} 1+\frac{1}{1+\frac{1}{1+\frac{1}{1+\ddots}}} = \frac{1}{2} \left( 1+\sqrt{5} \right) \end{eqnarray}$
\begin{eqnarray} 1+\frac{1}{1+\frac{1}{1+\frac{1}{1+\ddots}}} = \frac{1}{2} \left( 1+\sqrt{5} \right) \end{eqnarray}
The diagonal dots indicate that it goes on forever.
$0.123$
0.123
A period is used for the decimal point.
$\frac{1}{11} = 0.\dot{0}\dot{9}$
\frac{1}{11} = 0.\dot{0}\dot{9}
To add dot on top of a number, use \dot.
$\pi = 3.14 \ldots$
\pi = 3.14 \ldots
Here's a sample to add three points to the bottom.
$\sqrt{2} = 1.4142 \cdots$
\sqrt{2} = 1.4142 \cdots
Here's a sample to add three points in the middle.
$\infty$
\infty
\infty comes from "infinity".
$|x|$
|x|
Absolute values can be represented by a vertical line symbol.
$\vert x \vert$
\vert x \vert
A vertical line used for absolute values can also be represented by vert, which comes from vertical line.
$\left| \dfrac{x}{2} \right|$
\left| \dfrac{x}{2} \right|
If you add \left and \right before the vertical lines, the vertical lines will be longer to match the size of the fraction.
$\require{physics} \qty|\dfrac{x}{2}|$
\require{physics} \qty|\dfrac{x}{2}|
\qty in the physics extension allows you to write fractions with absolute value symbols a little simpler. \qty comes from physical quantity.
$\require{physics} \abs{ \dfrac{x}{2} }$
\require{physics} \abs{ \dfrac{x}{2} }
\abs in the physics extension allows you to write fractions with absolute value symbols. \abs comes from "absolute value".
$[x]$
[x]
The Gauss brackets can be represented by a square bracket symbol.
$\lbrack x \rbrack$
\lbrack x \rbrack
The Gauss brackets can also be represented with \lbrack and \rblack. They come from the left bracket and the right bracket.
$\lfloor x \rfloor$
\lfloor x \rfloor
They come from "floor function".
$\lceil x \rceil$
\lceil x \rceil
They come from "ceiling function".
$\begin{eqnarray} [x] = \lfloor x \rfloor = \max\{ n\in\mathbb{Z} \mid n \leqq x \} \end{eqnarray}$
\begin{eqnarray} [x] = \lfloor x \rfloor = \max\{ n\in\mathbb{Z} \mid n \leqq x \} \end{eqnarray}
The definition of the Gaussian brackets.