Calculates the arcus sine of the argument, which is the inverse of the function SIN. If the argument is not between (-1.0,+1.0) the return value is undef.
If the result is within the range of an integer value on the actual architecture then the result is returned as an integer, otherwise it is returned as a real value.
ASIN(undef) is undef or raises an error if the option RaiseMatherror is set in bit sbMathErrUndef.