Domain:  set of all values for the independent variable (x).
 Range:  set of all values for the dependent variable (y).
  
 f(x)  =  | 1 - x |     Domain = all real numbers
                            Range = all real number >= 0.
  
 f(t)  =  sqrt( 2 - t )     Domain = all real numbers >= 2
                                 Range = all real numbers >= 0