The functions in this group can all be used on real or double precision arguments, and SIN and COS can also be used on complex numbers. In every case the result has the same data type as the argument.
Note that the arguments of SIN, COS, and TAN must be angles
measured in radians (not degrees). They can be used on angles of
any size, positive or negative, but if the magnitude is very large the
accuracy of the result will be reduced. Similarly all the inverse
trigonometric functions deliver a result in radians; the argument of
ASIN and ACOS must be in the range -1 to +1.
The ATAN2 function can be useful in resolving a result into
the correct quadrant of the circle, thus:
ATAN(0.5) = 0.4636476
ATAN2(2.0,4.0) = 0.4636476
ATAN2(-2.0,-4.0) = -2.677945 ( = 0.4636476 - 
).