acos [function]

acos( x )

returns the arccosine of x (angle in radians), as real

• If x is outside the [-1,1] range, function returns null and emits a warning message

acos( -1 ); // real (3.14159)
acos( 0 ); // real (1.5708)
acos( 2 ); // null; Warning: acos(): mathematical error