# 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.

## Usage

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

Parameters:
1. angle (required):
The angle in radians for which to calculate the cosine. This should be a numeric value.

## Examples

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

### Calculate the cosine of an angle

The `COS` function can be used to calculate the cosine of an angle in radians. For example, to calculate the cosine of 45 degrees, which is pi/4 radians, you can use the formula `=COS(PI()/4)`.

### Calculate the length of a side of a right triangle

The `COS` function can be used to calculate the length of a side of a right triangle given an angle and the length of another side. For example, if you know the length of the hypotenuse of a right triangle and one of the angles, you can use the `COS` function to calculate the length of the adjacent side.

### Calculate the distance between two points

The `COS` function can be used to calculate the distance between two points on a sphere given their latitudes and longitudes. This is known as the great-circle distance.

## Common Mistakes

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

### Incorrect argument type

Make sure the argument for the COS function is a numeric value representing the angle in radians.

The COS function uses radians as its unit of measurement. If you have an angle in degrees, you need to convert it to radians first.

### Mismatched parentheses

If you're getting a formula parse error, make sure your parentheses match up correctly.

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

• `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.

• `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.

• `ACOS`

The `ACOS` function returns the arccosine of a value, which is the angle in radians whose cosine is the specified value. The function is often used in trigonometry to find the angle of a right triangle given the adjacent and hypotenuse. The value parameter must be a number between -1 and 1.

• `ATAN2`

Returns the arctangent of the quotient of its arguments. ATAN2 is similar to ATAN, except that ATAN2 allows for two arguments and returns the angle of the result in the appropriate quadrant. This function is commonly used to calculate the angle between two points in a 2D plane. The angle is measured in radians and ranges from -pi to pi.

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