# ATAN

The `ATAN` function returns the arctangent of a value in radians, which is the angle whose tangent is a given value. This function is commonly used in trigonometry and geometry to calculate angles. The returned angle is in the range -π/2 to π/2.

## Usage

Use the `ATAN` formula with the syntax shown below, it has 1 required parameter:

Parameters:
1. value (required):
The value for which to calculate the arctangent. Must be a numeric value.

## Examples

Here are a few example use cases that explain how to use the `ATAN` formula in Google Sheets.

### Calculate the angle of a right triangle

Given the length of two sides of a right triangle, you can use the `ATAN` function to calculate the angle opposite the first side. For example, if you know the length of the adjacent side and the length of the hypotenuse, you can use `ATAN` to calculate the angle of elevation.

### Calculate the angle between two points

If you have the coordinates of two points in a plane, you can use `ATAN` to calculate the angle between the line connecting the two points and the horizontal axis.

### Calculate the slope of a line

The slope of a line is the tangent of the angle between the line and the horizontal axis. You can use `ATAN` to calculate the angle and then take the tangent to get the slope.

## Common Mistakes

`ATAN` not working? Here are some common mistakes people make when using the `ATAN` Google Sheets Formula:

The ATAN function in Google Sheets returns the result in radians. If you want to use degrees, you need to convert your values to radians first. To convert degrees to radians, multiply by PI()/180.

### Using text values instead of numbers

The ATAN function in Google Sheets only works with numerical values. If you try to use text values, it will return an error. Make sure that you are using numerical values in your formula.

### Forgetting to close the parentheses

Make sure that you close the parentheses of the ATAN function properly. If you forget to close them, Google Sheets will return an error.

The following functions are similar to `ATAN` or are often used with it in a formula:

• `TAN`

The `TAN` function returns the tangent of an angle specified in radians. Tangent is the ratio of the length of the opposite side to the length of the adjacent side of a right-angled triangle. This function is commonly used in trigonometry and geometry calculations.

• `COS`

The `COS` function in Google Sheets returns the cosine of an angle provided in radians. It is commonly used in trigonometry to calculate the cosine of an angle. The function takes one parameter, the angle in radians.

• `SIN`

The `SIN` function in Google Sheets returns the sine of a given angle in radians. Sine is a mathematical function that describes a smooth repetitive oscillation. It is commonly used in trigonometry, physics, and engineering to model phenomena such as waves, oscillations, and periodic motion.

You can learn more about the `ATAN` Google Sheets function on Google Support.