# How to insert an equation with integral

**Gauss's law**, also known as

**Gauss's flux theorem**.

How to add an equation in your document, see Working with Microsoft Equation.

To add an integral form of the **Gauss's law**, do the following:

## In the **Professional** format:

** 1. ** Create your own equation.

** 2. ** Under **Equation Tools**, on the **Design** tab,
in the **Structures** group, click the **Integral** button:

In the **Integral** list, choose **Contour Integral**:

** 3. ** In the integral template:

- In the lower box, enter
.**S** - In the upper box, right-click and choose
**Hide Upper limit**in the popup menu: - In the right base box, enter
.**E**

** 4. ** Under **Equation Tools**, on the **Design** tab,
in the **Symbols** group, in the list of symbols choose
.

** 5. ** Then enter * dA=*.

** 6. ** Under **Equation Tools**, on the **Design** tab,
in the **Structures** group, click the **Fraction** button. In the **Fraction** list
choose **Stacked Fraction**:

** 7. ** Enter * Q* at the top of your fraction.

** 8. ** In the bottom of your fraction, do the following:

- On the
**Equation Tools Design**tab, in the**Structures**group, click the**Script**button. - In the
**Script**list, choose**Subscript**: - On the
**Equation Tools Design**tab, in the**Symbols**group, in the list of symbols choose , - In the lower box of the subscript, enter
.**0**

## In the **Linear** format:

** 1. ** Create your own equation.

** 2. ** Do one of the following:

- Under
**Equation Tools**, on the**Design**tab, in the**Symbols**group, click the**More**button:In the top of the list of symbols, choose

**Operators**:

In the**Operators**list, choose . - Simply enter
.**\oint**

** 3. ** Enter * _S*. Then you enter a space key;
this linear formula transformed into a professional format.

** 4. ** In the base box of integral, enter * E*.

** 5. ** Under **Equation Tools**, on the **Design** tab,
in the **Symbols** group, choose
(or simply enter
* \bullet*).

** 6. ** Then enter * dA=Q/*,
choose (or simply
enter

*) and then*

**\varepsilon***:*

**_0**Then you enter a space key, your linear formula transformed into the professional format.

See also how to create other types of equations.

See also this tip in French: Comment insérer une équation avec l'intégrale.