Let C1 be the square oriented counterclockwise of vertices (0, 0), (0, 4), (4, 4), (4, 0) and let C2 be the triangle oriented counter clockwise with vertices (1, 1), (2, 1), (2, 2). Let F = ( P, Q) be a continuously differentiable vector field on the plane R2. Calculate JC F . dr , knowing that (a) J F . di = ev2 (b) curl( F) . k = 2n