Learning Resources

Investigation 1: Total Earnings & Focus A: Combination by Subtraction

• The domain must be the same in two functions if they are to be combined. In other words, functions can only be combined when restricted to their common domain.
• Thus, it stands to reason that the domain of the combined graph must equal the common domain of the two original graphs. The range would be the sum or difference of the range values of the original graph and would depend on the domain.