1. Combining functions: Revenue, Cost, and Profit The revenue, cost, and profit for a product, each in terms of dollars for sales of x units, are given below: Revenue Cost Profit We can refer to the function P as the difference of functions R and C

2. It can also be seen from the graph that profit is the difference of revenue and cost revenue - cost profit Revenue Cost Profit

3. Composition of functions: Evaporation rate Expected temperature T(h) for August 24 is a function of hour of day: Evaporation rate E(T) of a small lake is a function of outside temperature: Define evaporation rate as a function of hour of day: We can refer to the function P as the composition of functions E and T What do you expect the evaporation rate to be at 2:00?

4. Summary of combinations of functions NameNotationMeaning Sum of f and g Difference of f and g Product of f and g Quotient of f and g Composition of f and g