The reader may have observed that,

The reader may have observed that, while Figure 10.3 was concerned with the determination of optimal prices of joint products, Figure 10.4 was concerned with the determination of optimal outputs. The reason for this difference lies in the assumptions involved. There were a number of simplifying assumptions made in the model in Figure 10.4, for example only two products were involved. Most important in this context though is the assumption that the firm was a price-taker; thus the only relevant managerial decision was regarding the quantities of output. However, the price-taking assumption, which caused the total revenue curves to be linear, can easily be relaxed without affecting the analysis in any fundamental way. The profit-maximizing positions will still involve points of tangency between the total cost and total revenue curves. Once optimal outputs are determined, the prices of these outputs can be derived from the appropriate demand curves.