The ACOS() function calculates the arc cosine (inverse cosine) of a given numeric value.
Syntax
ACOS(number)
Definition and Usage
- The
ACOS()function returns the arc cosine of a number. - The result is expressed in radians and is in the range [0, π] (0 to approximately 3.14159).
- The input value must be between -1 and 1. If the value is outside this range, the function returns
NULL.
Parameter Values
| Parameter | Description |
|---|---|
number |
Required. A numeric value between -1 and 1. |
Technical Details
- Works in: From MySQL 4.0
Examples
Example 1: Arc cosine of a positive number
SELECT ACOS(0.25);
Result:
1.318116071652818
Example 2: Arc cosine of a negative number
SELECT ACOS(-0.8);
Result:
2.498091544796509
Example 3: Arc cosine of 1
SELECT ACOS(1);
Result:
0
Example 4: Arc cosine of -1
SELECT ACOS(-1);
Result:
3.141592653589793
Example 5: Input outside the range
SELECT ACOS(1.5);
Result:
NULL
Usage Notes
- Use the
ACOS()function in trigonometric calculations or geometry problems requiring inverse cosine. - To convert radians to degrees, multiply the result by 180π\frac{180}{\pi}:
SELECT ACOS(0.25) * (180 / PI());
Result in degrees:
75.52248781407008