This Demonstration shows plots of the conversion, production, and cost curves as functions of time. The green dot corresponds to the maximum production option, while the cyan dot represents the maximum profit (i.e., the minimum cost function). The cyan and green dots are obtained by making the orange and red lines tangent to the conversion versus time curve (i.e., the blue curve). The cost function, , is given by: , where and are the cost coefficients for the reaction and dead time and is the cost of miscellaneous expenses. The dead time is taken to be equal to 1 hour. It is clear that the two possible operating points (maximum profit and maximum production) do not coincide. Depending on the value of the parameters , , and , we conclude that it is often preferable to minimize costs even if this leads to smaller production, as can be seen in the cost versus time curve.