(5 points) Let F = (3z + 3x) + (6y + 6z + 6 sin(y )) j+ (3x + 6y + 6e) k. (a) Find curl F. curl F = (b) What does your answer to part (a) tell you about F. dr where Cis the circle (x 30)2 + (y 10)? = 1 in the xy-plane, oriented clockwise? SeF df = (c) If C is any closed curve, what can you say about F. dr? SoF di = (d) Now let C be the half circle (x - 30)? + (y 10)? = 1 in the xy-plane with y > 10, traversed from (31, 10) to (29, 10). Find , F. dr.