revenue? 5. Corey is asked to find the maximum value of a function. Not having a complete understanding of the process, Corey decides to find the derivative of the function, set it equal to zero, and solve. The resulting value, Corey reasons, will yield the maximum point. Explain fully why Corey's method is flawed. 6. A 5,000 m rectangular area of a field is to be enclosed by a fence, with a moveable inner fence built across the narrow part of the field, as shown. The perimeter fence costs $10/m and the inner fence costs $4/m. Determine the dimensions of the field to minimize the cost