1.20. Consider the comparative statics of the farmer’s fencing problem in Learning-By-Doing Exercise 1.4, where L is the length of the pen, W is the width, and A ! LW is the area.

a) Suppose the number of feet of fence given to the farmer was initially F1 ! 200. Complete the following table. Verify that the optimal design of the fence (the one yielding the largest area with a perimeter of 200 feet) would be a square.