# ACOS

Formulas / ACOS
Calculate the inverse cosine of a number.
ACOS(number)
• number - cosine of the angle, must be from -1 to 1

## Examples

• =ACOS(0.5) * 180/PI()

To convert it to degrees, use the formula above, where x is a number between -1 and 1. For example, the formula above returns 60 degrees.The ACOS function returns the arccosine of a number. The arccosine is the inverse of the cosine function, and is measured in radians.

• =ACOS(0.5)

The ACOS function can also return the arccosine in radians like in the formula above which returns 1.047 radians.

## Summary

The ACOS function in Excel is a trigonometric function that calculates the arccosine (inverse cosine) of a given number. The function returns an angle, measured in radians, whose cosine is the specified number.

• The ACOS function requires that its input is between -1 and 1 and returns an angle in radians.
• The angle returned by the ACOS function is the angle of a triangle when given the ratio of the adjacent side over the hypotenuse.
• The DEGREES function can be used to convert the result of ACOS to degrees.

What does the ACOS function do?
The ACOS function is used to return the inverse cosine of a number. This inverse cosine is also known as the arccosine, and it is the angle whose cosine is the number.
What is the argument of the ACOS function?
The argument of the ACOS function is a cosine of an angle.
What is the result of the ACOS function?
The result of the ACOS function is a number in radians.
What range of numbers can be used as arguments with the ACOS function?
The argument of ACOS must be a number from -1 to 1.
How can I convert the result of the ACOS function from radians to degrees?
You can convert the result of the ACOS function from radians to degrees using the DEGREES function, or by multiplying the result by 180/PI().