please explain

Section 13.3: Problem 3 (1 point] Consider the vector field F(r, y, 2) = zi + wj + zk. a) Find a function f such that F - V f and /(0, 0,0) = 0. f(s, y. =) b) Use part a) to compute the work done by F on a particle moving along the curve C' given by r(t) = (1 + 5sint)i + (1+ 2sin'#)j + (1 + 3sin't)k, ost