IsNan

Miscellaneous functions 
SYNTAX  IsNan( x ) 
RETURNS  NUMBER, ARRAY 
FUNCTION  Returns a nonzero value (1 or TRUE) if the argument x is a NaN; otherwise it returns 0 (FALSE). A NaN is generated when the result of a floatingpoint operation cannot be represented in Institute of Electrical and Electronics Engineers (IEEE) format. 
EXAMPLE  IsNan( 0/0 ); 
SEE ALSO  NZ() function 
The IsNan function is used in the following formulas in AFL online library:
See updated/extended version online.