## Symbols

In general, you have to search in long tables about a specific symbol you’re looking for, things like $\Psi$, $\delta$, $\zeta$, $\ge$, $\subseteq$ … And it turns out that this operation can be frustrating and time consuming, which can cause the buddy to abandon writing the complete $\LaTeX$ sentence in his answer, or in some cases, the complete answer itself.

That’s why the tool that I will present you in this post was conceived. Basically, it is a $\LaTeX$ *handwritten symbol recognition*. Example in image:

Here is the website: Detexify²

No more frustration.

## Definitions by cases (piecewise functions)

Use `\begin{cases}…\end{cases}`

. End each case with a `\\`

, and use `& `

before parts that should be aligned.

For example, you get this:

$$f(n) =

\begin{cases}

n/2, & \text{if $n$ is even} \\

3n+1, & \text{if $n$ is odd}

\end{cases}$$

by writing this:

1 2 3 4 5 | f(n) = \begin{cases} n/2, & \text{if $n$ is even} \\ 3n+1, & \text{if $n$ is odd} \end{cases} |

The brace can be moved to the right:

$$

\left.

\begin{array}{l}

\text{if $n$ is even:}& n/2\\

\text{if $n$ is odd:}& 3n+1

\end{array}

\right\}

=f(n)

$$

by writing this:

1 2 3 4 5 6 7 | \left. \begin{array}{l} \text{if $n$ is even:}& n/2\\ \text{if $n$ is odd:}& 3n+1 \end{array} \right\} =f(n) |

To get a larger vertical space between cases we can use `\\[2ex]`

instead of `\\`

. For example, you get this:

$$f(n) =

\begin{cases}

\frac{n}{2}, & \text{if $n$ is even} \\[2ex]

3n+1, & \text{if $n$ is odd}

\end{cases}$$

by writing this:

1 2 3 4 5 | f(n) = \begin{cases} \frac{n}{2}, & \text{if $n$ is even} \\[2ex] 3n+1, & \text{if $n$ is odd} \end{cases} |

(An ‘ex’ is a length equal to the height of the letter `x`

; `2ex`

here means the space should be two exes high.)