6.二重积分计算的两种积分顺序r=∫/(x,p)dy D:x1()≤x≤x2() D:y1(x)≤y≤y2(x) ≤y≤d a≤x<b y2(x) x10) x2() D D y1(x) x b x2(y) J2 f(x, y)dx f(x, y)dy 囧0 y x c d y D 0 y x I = a b y1 (x) y2(x) D x1 (y) x2(y) x 6. 二重积分计算的两种积分顺序 .  = D I f (x, y)dxdy    ( ) ( ) ( , )d y x y x I = f x y y    ( ) ( ) ( )d x y x y f x, y x  d c dy D: x1 (y)  x  x2 (y) c  y  d D: y1 (x)  y  y2 (x) a  x  b