Computes the arcsine (in radians) of the specified argument.
Format: Asin(exprn)
Arguments:
Return type: float
Error conditions: Returns 'Bottom' if exprn evaluates to 'Bottom', or if exprn is not in the domain of arcsine (which is [-1.0,1.0]).
Example:
value = asin(1)
; Sets value to the arcsine of 1, which is approximately pi/2 (possibly with some rounding error.)