(1)∫∫f(x,y)dxdy=∫dx∫f(x,y)dy (先积分y,再积分x)
=∫dy∫f(x,y)dx+∫dy∫f(x,y)dx (先积分x,再积分y);
(2)∫∫f(x,y)dxdy=∫dy∫f(x,y)dx (先积分x,再积分y)
=∫dx∫f(x,y)dy+∫dx∫f(x,y)dy (先积分y,再积分x).
(1)∫∫f(x,y)dxdy=∫dx∫f(x,y)dy (先积分y,再积分x)
=∫dy∫f(x,y)dx+∫dy∫f(x,y)dx (先积分x,再积分y);
(2)∫∫f(x,y)dxdy=∫dy∫f(x,y)dx (先积分x,再积分y)
=∫dx∫f(x,y)dy+∫dx∫f(x,y)dy (先积分y,再积分x).