= √(x − y) dx + 3x dy, I = where C consists of the four line segments from (1,0) to (3,0), then from (3,0) to (3,1), then from (3, 1) to (1, 1), and finally from (1, 1) to (1,0). The closed curve C is a rectangle with the four corners at (1,0), (3,0), (3, 1), (1, 1). In this problem, the value of I is not equal to the area of the rectangle. Rather, the value of I is k times the area of the rectangle. What is the value of k?