Returns
            the constant e (a real number) raised to a
            specified power (the natural antilog)
         
         
         Arguments
         
- num
 
            - 
               
            
 
         
         Return Values
         
         A real (num),
            raised to its natural antilogarithm.
         
         Examples
         
         Command: (exp
               1.0)
         2.71828
         Command: (exp
               2.2)
         9.02501
         Command: (exp
               -0.4)
         0.67032