Solve using calculus concepts (derivative to find minimum cost) and please show the steps clearly

all be enclosed. 4. A rectangular pigpen will be surrounded by a fence and then divided into two sections by a block wall. The area of the pigpen must be 32 m?. Fencing cost $20/m and the block wall costs $40/m. What should be the dimensions of the pigpen to minimize costs? 5. Find the area of the largest rectangle that can be inscribed in a right triangle with legs adjacent to the right angle of lengths 4