ACOS

Syntax: ACOS (x)                where x=-1...1
Location: QL ROM

The function ACOS, is the arc-cosine function, that is to say the opposite to the cosine function (COS in SuperBASIC).
Any value of x outside of the above range will produce an Overflow Error.

The angle returned will be in the range  0...PI with ACOS(1)=0 and ACOS(-1)=PI. This means that the maximum angle which can be found with ACOS is 180 degrees. It is up to you to check whether this angle appears above or below the base line of the triangle (check the co-ordinates of the corners).

Note that if a negative value of x is provided, the angle returned will be the obtuse angle (ie. greater than 90 degrees).

NOTE:
The angle returned will be in radians - use DEG to convert it to degrees.

CROSS-REFERENCE:
COS, ASIN, SIN, RAD.
Compare ARCOSH.
