ACos ( double value );    
Description
Returns the arc cosine of a value in the range from 0 through pi.
Input parameters
| Parameter | Default value | Description | 
|---|---|---|
| value | - | Defines argument whose arc cosine is returned. Values for this argument must be in the [-1;1] range. | 
Example
declare lower;
plot Data = Acos(0.5) == Double.Pi / 3;
The expression in the second line of code compares two values and draws a plot. If the two values are equal, it draws the unit (true) plot . Otherwise, it draws the zero (false) plot. The arc cosine of 0.5 equals pi/3. So the example draws the unit plot.