3. (25 Points.)
(a) Calculate the work done by the vector field
$\vec{F} = (2xyz^3)\vec{i} + (x^2z^3 + 2yz)\vec{j} + (3x^2yz^2 + y^2 + 3)\vec{k}$
in moving a particle along straight line segments from (0, 2, 1) to (-1, 2, 4), to (3, 0, 0), to (4, 0, -1).
(b) Calculate the work done by the vector field
$\vec{F} = (y + e^{\sin x})\vec{i} + 2x\vec{j}$
in moving a particle along the curve $y^2 = x$ from (9, -3) to (9, 3).