(c) yz dx + xz dy + Xy dz, where c consists of straight-line segments joining (2, 0, 0) to (0, 2, 0) to (0, 0, 2) x2 dx - xy dy + dz, where c is the parabola 2 = x2 , Y = 0 from (_2, 0, 4) to (2, 0, 4)