ACOS
TheACOS
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.
 How to use
ACOS
formula?  Examples of using
ACOS
formula ACOS
formula not working? Similar formulas to
ACOS
Usage
Use the ACOS
formula with the syntax shown below, it has 1 required parameter:
 value (required):
The value whose arccosine is to be returned. Must be a number between 1 and 1.
Examples
Here are a few example use cases that explain how to use theACOS
formula in Google Sheets.
Find the angle of a right triangle
Given the length of the adjacent and hypotenuse of a right triangle, you can use the ACOS
function to find the angle opposite to the adjacent side.
Calculate the inverse cosine of a value
The ACOS
function is used to calculate the arccosine of a given value, which is the angle whose cosine is that value.
Calculate the angle between two vectors
The ACOS
function can be used to find the angle between two vectors in threedimensional space.
Common Mistakes
ACOS
not working? Here are some common mistakes people make when using the ACOS
Google Sheets Formula:
Invalid argument type
The ACOS formula requires a numeric value as input. If the input is not a number, the formula will return an error. To fix this, make sure the input is a valid number.
Out of range input
The input value for ACOS must be between 1 and 1. If the input is outside this range, the formula will return an error. To fix this, make sure the input is within the valid range.
Incorrect syntax
The ACOS formula requires one input value. If there are too many or too few arguments, the formula will return an error. To fix this, check the syntax of the formula and make sure it has the correct number of arguments.
Related Formulas
The following functions are similar to ACOS
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. 
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. 
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 rightangled triangle. This function is commonly used in trigonometry and geometry calculations.
Learn More
You can learn more about the ACOS
Google Sheets function on Google Support.