One of my friends asked me if there is an easier way of knowing the definion of the computed column. Currently what he does is to script out the table definition and looks for the definition of computed column. Well. There is an easy way of finding it. You just need to query the system catelog view sys.computed_columns.  

Consider the following table

create table emp_salary(emp_id int, basic_sal decimal(12,2),bonus as 0.10*basic_sal)

select 
	object_name(object_id) as table_name,name as column_name,definition  
from 
	sys.computed_columns where object_id=object_id('emp_salary')

table_name                column_name    definition
------------------------- -------------  ----------------
emp_salary                bonus          ((0.10)*[basic_sal])