Use green's theorem to evaluate f · dr. c (check the orientation of the curve before applying the theorem.) f(x, y) = e−x + y2, e−y + x 2 , c consists of the arc of the curve y = cos(x) from − π 2 , 0 to π 2 , 0 and the line segment from π 2 , 0 to − π 2 , 0.