(2 points) (a) Let f(x, y) = xy' - re"+ r'. Find a function g(r, y) such that the vector field F(x,y) = (f(x, y), 9(r, y)) is conservative. (b) Let C be the piece of the curve y = va from (0, 0) to (4, 2), followed by the straight segment down to (4,0), and then a straight segment back to (0, 0). Compute fo f(z, y) de by arguing (via the FTLI) that it is the same as - fog(r, y) dy and computing the latter