SQL Server ACOS() Function

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Summary: in this tutorial, you will learn how to use the SQL Server ACOS() function to return the arccosine of a number.

Introduction to the SQL Server ACOS() function #

The arccosine function is the inverse function of the cosine function. The arccosine returns the angle of a cosine in radians.

In SQL Server, you can use the ACOS() function that returns an angle (in radians) of a specified cosine.

Here’s the syntax of the ACOS() function:

ACOS(n)Copy

In this syntax:

• n is a float value you want to calculate the arccosine. The valid range of n is from -1 to 1.

The ACOS() function returns an angle (in radians) whose cosine equals the n. If n is invalid, the ACOS() function will raise an error. If n is NULL, the ACOS() function will return NULL.

SQL Server ACOS() function examples #

Let’s take some examples of using the SQL Server ACOS() function.

1) Basic SQL Server ACOS() function example #

The following example uses the ACOS() function to return the arccosine of -1:

SELECT ACOS(-1) angle;Copy

Output:

angle
-----------------
3.141592653589793Copy

It returns the PI value.

2) Using ACOS() function with variables #

The following example uses the ACOS() function with variables:

DECLARE @value FLOAT;
SET @value = 1;

SELECT ACOS(@value) AS arccosine_value;Copy

Output:

arccosine_value
---------------
0Copy

In this example, we set the @value to 1 and then use the ACOS() function to calculate the arccosine of 1, which is zero radians.

Summary #

• Use the ACOS() function to return the arccosine of a number.