# SQLite ACOS function

The ACOS function in SQLite is a mathematical function that returns the inverse cosine of a given value in radians. In other words, it calculates the angle whose cosine is equal to the specified value. The function takes a single argument, which is a numeric value between -1 and 1.

## Syntax

The syntax for the ACOS function in SQLite is as follows:

```ACOS(x)
```

Here, x is the numeric value whose inverse cosine needs to be calculated. The function returns the result in radians.

### Example

For example, if we want to calculate the inverse cosine of 0.5, we can use the ACOS function as follows:

```SELECT ACOS(0.5);
```

This will return the result 1.0471975511966, which is the angle whose cosine is 0.5 in radians.

It is important to note that the argument to the ACOS function must be a number between -1 and 1. If the argument is outside this range, the function will return NULL. Additionally, the argument should be expressed in radians, not degrees. If the argument is in degrees, it must be converted to radians before using it with the ACOS function.

In summary, the ACOS function in SQLite is a useful mathematical function that can be used to calculate the inverse cosine of a given value in radians.