A rectangular garden with it's sides surrounded by a fence. The perimeter of the garden is 100 m, which is the same length of the fence. (i) Show that the area of the garden is equal to: A = 50 z - z- where A is the area and z is one of the side of the garden. (ii) Use the second derivative test to find the value of z for the maximum area of the garden. (iii) Calculate the area of the garden