9-14 Show that the integral is independent of the path, and use Theorem 15.3.1 to find its value. (4.0) 9. 3y dx + 3x dy (1.2) (1, 71 / 2) 10. esin ydx + e cosy dy (0,0) . (3.2) 11. 2 xe " dx + x e" dy (0.0) . (0,1) 12. (3x - y + 1) dx - (x + 4y+2) dy (- 1.2) .(-1,0) 13. 2xy' dx + 3y x2 dy .J ( 2.-2)