I.4.47 Curvilinear Integrals

Condition: calculate the curved integral \ (\ int_ {l} f (x, y) d x+g (x, y) d y \) \ (f (x, y) = x^{2} -y, \ quad g (x, y) = y^{2} -x \), \ (\) rectangle \ (\ (\ (\ (\ (\ (\ (\ (\ (( x = 0, y = 0, x = 1, y = 2 \).