# \infty

The ∞ symbol (Infinity, U+221E), written as \infty in LaTeX math mode.

https://texform.dev/latex/symbols/infty

## Metadata

| Field | Value |
| --- | --- |
| Topic | [Letter-like symbols](https://texform.dev/latex/topics/letter-like) |
| Packages | base |
| Allowed mode | math |
| Glyph | ∞ |
| Unicode | U+221E INFINITY |
| Delimiter | No |

## Syntax

```latex
\infty
```

Takes no arguments.

## Common tasks

### How to write infinity

```latex
\infty
```

[Open in Playground](https://play.texform.dev/?input=%5Cinfty)

### How to write an integral over the line

```latex
\int_{-\infty}^{\infty} f(x)\,dx
```

[Open in Playground](https://play.texform.dev/?input=%5Cint_%7B-%5Cinfty%7D%5E%7B%5Cinfty%7D+f%28x%29%5C%2Cdx)

### How to write a limit at infinity

```latex
\lim_{x\to\infty} f(x)
```

[Open in Playground](https://play.texform.dev/?input=%5Clim_%7Bx%5Cto%5Cinfty%7D+f%28x%29)

## Usage frequency

7.92% of formulas in the measured corpus contain this entry, rank 9 of 474 entries with frequency data.

## In TeXForm

TeXForm parses this entry as a character leaf mapped to U+221E (INFINITY).

## See also

- [\\backslash](https://texform.dev/latex/symbols/backslash)
- [\\lnot](https://texform.dev/latex/symbols/lnot)
- [\\neg](https://texform.dev/latex/symbols/neg)