# How to Write Double Integral (∫∫) Symbol in LaTeX

**To write double integral symbol (∫∫) in LaTeX, use the LaTeX command \iint. It will add ∫∫ symbol in the text.**

In this article, we will discuss how to use calculus double integral symbol (∫∫) in the LaTeX document and its significance in the mathematical expressions and physics.

## Symbol Overview

**Symbol:** Double Integral

**Unicode:** U+222C

**Type:** Mathematical

**Package Requirement:** None (built-in symbol)

**Argument:** None (no additional arguments needed)

**LaTeX Command:** \iint

**Example:** ∫∫

## Description

The **double integral symbol (∫∫)** is built-in symbol available in LaTeX,denoted by command `\iint`

. It is used to represent double integral in mathematics. It is widely used in calculus, differential equations, and various fields of physics.

## Syntax

The LaTeX command `\iint`

is used to write the **double integral** symbol.

```
\iint
```

## Using the Double Integral Symbol in Mathematical Expression

```
\documentclass{article}
\begin{document}
$\[ \iint R f(x, y) \, dx \, dy \]$
\end{document}
```

Output 👇️

∬_{R}f(x,y)dxdy

In this example, the double integral symbol is used to represent the integration of the function f(x,y) over a region R in the Cartesian plane.

## Using the Double Integral Symbol in Physics

```
\documentclass{article}
\begin{document}
\[ \iint_S \mathbf{F} \cdot d\mathbf{S} \]
\end{document}
```

Output 👇️

∬_{S}F⋅dS

Here, in the above example, the double integral symbol is used to calculate the flux of the vector field F across a surface S in Physics.

## Using the `amsmath`

Package to Use Double Integral Symbol

```
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[ \iint_R f(x, y) \, dxdy \]
\end{document}
```

Output 👇️

∬_{R}f(x,y)dxdy

In the above example, it uses the `amsmath`

package for mathematical typesetting. In LaTeX document, type `\usepackage{amsmath}`

to use double integral symbol in your document.

## Using the `mathtools`

Package to Use Double Integral Symbol

```
\documentclass{article}
\usepackage{mathtools}
\begin{document}
\[ \iint_R f(x, y) \, \mathrm{d}x \, \mathrm{d}y \]
\end{document}
```

Output 👇️

∬_{R}f(x,y)dxdy

Here, in this example, it uses `mathtools`

package for better control of spacing. Type `usepackage{mathtools}`

to use double integral symbol in your document. It provides enhanced control over spacing.

## Applications

The `double integral`

symbol has extensive applications various mathematical and scientific fields such as:

- Solve partial differential equations involving two variables.
- Calculation of flux, work, and other physical quantities in physics.

## Conclusion

The double integral symbol (∫∫) is a fundamental mathematical symbol used widely in calculus,physics and engineering.

Using the above syntax and examples presented in this article, you can write and use double integral symbol in your LaTeX documents to represent the integration and solve complex mathematical expressions.