Evaluate each of the following line integrals. (a) c(t) = (2 cost), 2 sin(t)), x dy-y dx, JC 2Ï t (b) x dy + y dx, c(t) = (cos(t), sin(mt)), 2 t 4 (c)yz dx + xz dy + xy dz, where c consists of straight-line segments joining (1, 0, 0) to (0, 1, 0) to (0, 0, 1) (d) x2 dx-xy dy + dz, where c is the parabola z = x2, y = 0 from (-1, 0, 1) to (1, 0, 1)